Perhaps in no other era of baseball has the role of the reliever become so paramount. As recent postseasons have shown, bullpens have often been the catalyst, or at least a vital piece, for championship-contending clubs.

As the roles of relievers have become less specialized, the save has remained a coveted measure of some of the game's most dominant bullpen arms. With that in mind, MLB.com examined the single-season saves leaders for each of the 30 teams.

AMERICAN LEAGUE EAST

Blue Jays: Duane Ward, 45 saves, 1993
Next best: Roberto Osuna, 39, 2017
Ward was a big part of Toronto's second consecutive World Series-winning season, leading the AL in saves in 1993 while earning his only career All-Star nod and finishing fifth in the AL Cy Young Award voting. In the Fall Classic that year, Ward saved two of the Blue Jays' wins over the Phillies -- Games 1 and 4 -- and he was the winning pitcher in the deciding Game 6, pitching a scoreless top of the ninth before Joe Carter ended the Series with his iconic walk-off homer in the bottom of the ninth.

Orioles: Jim Johnson, 51 saves, 2012
Next best: Johnson, 50, 2013
Johnson broke out with an All-Star campaign for Baltimore in 2012 -- his first of back-to-back 50-save seasons. His Major League-best 51 saves helped the O's make their first postseason appearance since 1997. Johnson finished seventh in the AL Cy Young Award voting, and he closed out the Orioles' AL Wild Card Game win over the Rangers and both of their Division Series wins against the Yankees (although he also had a loss and a blown save in the series, which Baltimore lost in five games). Johnson is one of only three pitchers in Major League history to save 50-plus games twice, along with Eric Gagne ('02-03) and Mariano Rivera ('01 and '04).

Rays: Fernando Rodney, 48 saves, 2012
Next best: Alex Colomé, 47, 2017
The well-traveled Rodney saved 30-plus games in a season with four teams -- the Tigers, Rays, Mariners and D-backs -- and the ones with Tampa Bay and Seattle were both 48-save seasons. Rodney's 2012 season with the Rays, though, was the best of his career. In fact, it's one of the best ever by a closer. Rodney not only saved 48 games, he had an ERA of just 0.60 -- setting a record at the time for the lowest in history by a reliever with at least 50 innings pitched. (Zack Britton passed him with a 0.54 ERA in '16.) Rodney was a '12 All-Star and finished fifth in AL Cy Young Award voting that season.

Red Sox: Tom Gordon, 46 saves, 1998
Next best: Craig Kimbrel, 42, 2018; Derek Lowe, 42, 2000
Gordon was a starter for the first 10 years of his career, even winning 17 games in 1989 while finishing second to Baltimore's Gregg Olson (and one spot ahead of Ken Griffey Jr.!) in the AL Rookie of the Year Award voting. But the Sox moved Gordon to the bullpen full-time in 1998, and he never started again after leading the AL in saves and games finished (69) that year.

Yankees: Mariano Rivera, 53 saves, 2004
Next best: Rivera, 50, 2001
No surprise here. Rivera, MLB's all-time career saves leader with 652, of course holds the Yankees' single-season mark. Mo's 53 saves in 2004 gave him his second career 50-save season, putting him in the group of three with Gagne and Johnson as the only pitchers to hit that mark twice. Rivera was an All-Star for the sixth time (of 13 career selections) in '04, and he finished third in the AL Cy Young Award voting as the Yanks won the AL East for a seventh straight season.

AL CENTRAL
Guardians: Jose Mesa, 46 saves, 1995
Next best: Joe Borowski, 45, 2007; Bob Wickman, 45, 2005
Mesa was as dominant as closers come in 1995, saving 46 games over a strike-shortened 144-game schedule. He posted a 1.13 ERA and 1.03 WHIP for the AL champions, finishing second in the AL Cy Young Award voting to Randy Johnson. It was an incredible season for Mesa and a 100-win Cleveland club, but it ended with a six-game loss to the Braves in the World Series. Mesa would go on to save 40 or more games three more times in his 19-year career -- in 2001 (42) and '02 (45) with the Phillies, and in '04 (43) with the Pirates.

Royals: Greg Holland, 47 saves, 2013
Next best: Holland, 46, 2014
In the season before the Royals truly burst onto the scene with a run to the World Series in 2014, Holland set the franchise record with 47 saves. It was a career year for the right-hander, who posted a 1.21 ERA in 68 appearances, striking out 103 of the 255 batters he faced (40.4 percent). Holland would be the closer for a vaunted Kansas City bullpen that played a key role in getting the club to the Fall Classic in '14 (seven-game loss to the Giants) and again in '15, when the Royals won their first title in 30 years (although Holland's season was cut short by injury).

Tigers: Jose Valverde, 49 saves, 2011
Next best: Francisco Rodriguez, 44, 2016
Valverde was among the game's best closers from 2007-11, a span during which he saved 191 games and had a 2.74 ERA for the D-backs, Astros and Tigers. But '11 was a career year for the right-hander, as he posted a 2.24 ERA and set a franchise record with 49 saves to help Detroit reach the postseason for the first time in five years. Valverde was hit hard in six playoff appearances, however, surrendering six runs in 7 1/3 innings against the Yankees and Rangers.

Twins: Joe Nathan, 47 saves, 2009
Next best: Eddie Guardado, 45, 2002
Nathan originally came up with the Giants as a starting pitcher, but after San Francisco traded him to Minnesota in 2003 in a package for catcher A.J. Pierzynski, the Twins converted Nathan to a reliever, and he became one of the best closers in baseball. He would go on to save 260 games and make four All-Star teams over seven seasons with Minnesota, including a franchise-record 47 saves in '09.

White Sox: Bobby Thigpen, 57 saves, 1990
Next best: Keith Foulke, 42, 2001
Until Francisco Rodriguez broke it with the Angels in 2008, Thigpen's 57 saves for Chicago in 1990 was the single-season record. Though he had saved 34 games in each of the previous two seasons, Thigpen's '90 campaign was by far the best of his career. His ERA was 1.83 and he finished fourth in AL Cy Young Award voting and fifth in AL Most Valuable Player Award voting.

AL WEST

Angels: Francisco Rodriguez, 62 saves, 2008
Next best: Brian Fuentes, 48, 2009
Rodriguez posted a trio of 40-save seasons from 2005-07 to establish himself as one of the premier young relievers of the day, but his historic '08 season put him in hallowed ground. He became the only pitcher in MLB history to surpass 60 saves, and his 62 saves remain the single-season mark to beat. Along the way, K-Rod finished third in the AL Cy Young Award voting and sixth in the AL MVP Award tally. He also became the youngest closer to register his 200th save. Rodriguez's record campaign earned him a three-year, $37 million contract with the Mets the following offseason.

Astros: Valverde, 44 saves, 2008; Billy Wagner, 44, '03
Next best: Brad Lidge, 42, 2005
Valverde only spent two of his 12 big league seasons with the Astros, but he was a bright spot amid a largely forgettable stretch in Houston history, when he saved an NL-best 44 of the Astros' 86 wins in 2008 -- his first year with the club -- to tie the franchise's all-time mark. Wagner's '03 season was the last of his nine years in Houston, and he posted his best numbers since he finished fourth in National League Cy Young Award voting in 1999, notching a career-best 44 saves and a 1.78 ERA in '03.

Athletics: Dennis Eckersley, 51 saves, 1992
Next best: Eckersley, 48, 1990
Eckersley likely would not win the AL MVP Award in today's game for the kind of season he put together in 1992, but that shouldn't take away from the achievements that netted him both the AL Cy Young Award and the AL MVP Award that year, as the A's raced to their fourth AL Championship Series in five seasons. Eck's 51 saves led MLB by a wide margin, while his 1.91 ERA was the third-best mark of his career (his career-best 0.61 ERA and 48 saves in 1990 didn't garner nearly as many votes for the major awards). The Hall of Famer's numbers took a sharp downturn a year later, but he saved 151 more games over his final six seasons.

Mariners: Edwin Díaz, 57 saves, 2018
Next best: Fernando Rodney, 48, 2014
Though over 15 batters per nine innings became strikeout victims to Díaz's electric fastball and slider in 2018, the most prominent casualty of the young fireballer's quest for the history books was Seattle manager Scott Servais' hair, after the skipper promised to match Díaz's creative hairdo if the closer could reach 50 saves. Though Díaz came six saves shy of breaking Francisco Rodriguez's MLB record of 62 set in 2008, the Mariners' righty enjoyed the club's best season for a reliever. Seattle finished the season 66-0 in games in which Díaz entered with a lead.

Rangers: Francisco Cordero, 49 saves, 2004
Next best: Joe Nathan, 43, 2013
Cordero took over the Rangers' closer job during the 2003 season following the trade of Ugueth Urbina to the Marlins, and in Cordero's first full season as the closer in '04, he set Texas' single-season mark with 49 saves and was named to an All-Star team for the first time in his career. Cordero was traded to Milwaukee in '06, and he made two more All-Star appearances in '07 (with the Brewers) and '09 (with the Reds), saving 210 games in the NL in his 14-year career.

NATIONAL LEAGUE EAST

Braves: John Smoltz, 55 saves, 2002
Next best: Craig Kimbrel, 50, 2013
After forming arguably the greatest starting rotation of all-time with fellow Hall of Famers Greg Maddux and Tom Glavine on the Braves' dominant teams of the 1990s, Tommy John surgery forced Smoltz to reinvent himself as a reliever. In 2002 -- his first full season as Atlanta's closer -- Smoltz set the NL record with 55 saves for his first of three consecutive 40-save seasons, as the Braves won the 11th of their record 14 straight division titles. Gagne tied Smoltz's 53-save mark the next season with the Dodgers, but no NL reliever has exceeded that total.

Marlins: Armando Benitez, 47 saves, 2004
Next best: Antonio Alfonseca, 45, 2000
Benitez had his ups and downs after establishing himself as the Mets' closer in the late 1990s, but his 2004 season with the Marlins was the best statistical year of his career. His 47 saves led the NL, and he had an ERA of just 1.29, his lowest in any full season. From April 8 through June 4, Benitez did not allow an earned run in 27 appearances while collecting 20 saves in that span. He also earned the second of his two career All-Star nods in '04.

Mets: Jeurys Familia, 51 saves, 2016
Next best: Familia, 43, 2015; Armando Benitez, 43, 2001
Familia led the Majors in saves in 2016, helping the Mets make the playoffs for a second straight year as one of the NL Wild Card teams. Familia's 51 saves in '16 eclipsed his own franchise record established the year before, when he saved 43 games and the Mets won the NL East. In the '16 Wild Card Game, though, Familia gave up the decisive three-run homer in the ninth inning of a scoreless game, and the Mets fell to the Giants.

Nationals: Chad Cordero, 47 saves, 2005
Next best: Rafael Soriano, 43, 2013; Drew Storen, 43, 2011;
Cordero was one of the bright spots for the Nationals in their first season in D.C., as he saved a Major League-best 47 games with a 1.82 ERA in an All-Star campaign. He saved 15 games in June alone, tying the MLB record for the most within a single calendar month, along with John Wetteland's 15 saves for the Yankees in June 1996 and Lee Smith's 15 for the Cardinals in June 1993. Cordero finished fifth in the NL Cy Young Award voting. (Wetteland also saved 43 games for the 1993 Expos, before the franchise moved to Washington).

Phillies: Jose Mesa, 45 saves, 2002
Next best: Mitch Williams, 43, 1993
The Phillies are the second team that has Mesa sitting atop its single-season saves list, as he also owns Cleveland's record with his 46 saves in 1995. That was the only season in which Mesa saved more games than he did for Philadelphia in 2002, when he posted his second straight 40-save season with the Phils after joining the team in '01 and saving 42 games.

NL CENTRAL

Brewers: John Axford, 46 saves, 2011
Next best: Francisco Rodriguez, 44, 2014; Francisco Cordero, 44, 2007
The Brewers reached the postseason in 2011 for the second time since 1982, in no small part thanks to a dominant season from Axford. The right-hander was in his third big league season, and it became his best thus far, as he posted a 1.95 ERA and finished ninth in the NL Cy Young Award voting. Axford also saved three games in the postseason (one in the NL Division Series against the D-backs and two in the NL Championship Series against the Cardinals).

Cardinals: Trevor Rosenthal, 48 saves, 2015
Next best: Jason Isringhausen, 47, 2004; Lee Smith, 47, 1991
Before injuries interfered, Rosenthal used his 100-mph fastball to put together a two-season stretch from 2014-15 for St. Louis in which he was dominant, particularly in '15. That's when he set the franchise record for saves, posted a 2.10 ERA and was named an NL All-Star.

Cubs: Randy Myers, 53 saves, 1993
Next best: Rod Beck, 51, 1998
Of the 347 career saves Myers recorded over a 14-year MLB career, 112 came during his three seasons with the Cubs from 1993-95. Though the best year of his career came earlier with the Reds as part of the "Nasty Boys" relief corps, including a 1990 World Series championship, the '93 campaign was his finest with the Cubs. Chicago didn't make the postseason that year, but the left-hander notched a save in 63 percent of the club's 84 victories while posting a 3.11 ERA.

Pirates: Mark Melancon, 51 saves, 2015
Next best: Mike Williams, 46, 2002
Melancon's emergence as a strong reliever was one of the keys to the Pirates breaking their 20-season playoff drought with an appearance in the NL Wild Card Game in 2013. The right-hander got better and better, becoming Pittsburgh's full-time closer in '14. But it was the next season that he put himself into the echelon of elite closers, saving a franchise-record 51 games while posting a 2.23 ERA and 0.93 WHIP. In 3 1/2 seasons with the Bucs, Melancon saved 130 games with a 1.80 ERA.

Reds: Jeff Brantley, 44 saves, 1996
Next best: Jeff Shaw, 42, 1997
Brantley had been a solid reliever for eight Major League seasons entering the 1996 campaign, but he had never saved more than 28 games. When the Reds signed the right-hander as a free agent prior to the '94 season, they made a solid investment that returned a 2.64 ERA and 88 saves over four seasons, including a franchise-record 44 in '96.

NL WEST

D-backs: Jose Valverde, 47 saves, 2007
Next best: J.J. Putz, 45, 2011
The D-backs tried out Valverde as their closer immediately upon his debut in 2003, but an injury in '04 and inconsistency the following two seasons prevented him from fully seizing the role. All that changed in '07, when Valverde held the closer job from Opening Day through Arizona's run to the NLCS. He set the young franchise's single-season record with a Majors-best 47 saves. Valverde saved his postseason debut in the NLDS against the Cubs, but took the loss in his only NLCS appearance as the Rockies swept the D-backs in four games.

Dodgers: Eric Gagne, 55 saves, 2003
Next best: Gagne, 52, 2002
Of course, it's Gagne who tops the Dodgers' leaderboard with his legendary 2003 season, when he converted all 55 of his save opportunities to tie Smoltz's NL record from a year earlier. That '03 season was just part of Gagne's MLB-record 84 consecutive saves converted from '02-04, but it certainly represented his peak during that stretch, as Gagne posted a career-low 1.20 ERA and struck out 15 batters per nine innings, which was, at the time, the best ever among relievers with at least 40 appearances. For his effort, he became the first reliever to win a Cy Young Award since Eckersley's 1992 AL MVP Award campaign -- and no relief pitcher has won since.

Giants: Brian Wilson, 48 saves, 2010; Rod Beck, 48, 1993
Next best: Robb Nen, 45, 2001
A young, beardless Wilson assumed the Giants' closer role in September 2007, and while he saved 79 games and was named to his first All-Star Game over the following two seasons, Wilson unleashed his full potential in '10, posting a career-best 1.81 ERA and a Majors-best 48 saves while pushing the Giants to their first World Series championship in 56 years. It was during that postseason run that Wilson began growing his trademark beard, as he saved six playoff games, including the decisive World Series Game 5. Wilson matched Beck's breakout 1993 campaign, when Beck saved 48 games as a 24-year-old in the first of five full seasons as San Francisco's closer.

Padres: Trevor Hoffman, 53 saves, 1998
Next best: Heath Bell, 47, 2010
The newly minted Hall of Famer had the best season of his 18-year career in 1998, when his 53 saves led the Majors as the Padres won the National League pennant for the second time in franchise history. It marked the first of seven All-Star campaigns for the game's second-most prolific closer, who posted the only 50-save season of his career. Hoffman made eight appearances during the '98 postseason, collecting three saves but blowing a save in his only World Series outing, as the Yankees swept the Padres in four games.

Rockies: Wade Davis, 43 saves, 2018
Next best: Greg Holland, 41 saves, 2017; Jose Jimenez, 41, 2002
In his first season after signing a record contract for a closer (in terms of average annual value), Davis converted a franchise-record 43 saves for Colorado over 69 outings. Davis had his bumps along the way, with six blown saves in what amounted to some of the Rockies' worst losses in 2018, but his bright spots proved paramount, as Colorado reached the postseason by claiming the second NL Wild Card spot, thanks in large part to its bullpen. The 43 saves also marked a career high for Davis, who had also pitched for postseason bullpens with the Cubs in 2017 and Royals from 2014-15 before joining Colorado.