There's no resting on your laurels in Major League Baseball, even when you just won the World Series.
That's the situation facing the Astros heading into 2023. If Houston is going to become the first team to repeat since the 2000 Yankees, then making an offseason splash certainly wouldn't hurt.
With that in mind, here's a look at some of the biggest and most successful additions reigning World Series champions have made. To be clear, this applies only to moves made in the offseason (free-agent signings or trades) and does not include players re-signing with the club.
2022 Braves: 1B Matt Olson
Acquired in trade with A's (March 14, 2022)
As baseball returned from a lockout that ate up much of the offseason, one of the big remaining questions was whether Atlanta would re-sign franchise cornerstone Freddie Freeman, who reached free agency after the club's title run. Instead, president of baseball operations Alex Anthopoulos swung a deal for a younger star first baseman, sending four prospects to Oakland to land Olson. The Braves then wasted no time in inking Olson to an eight-year, $168 million contract, preventing him from reaching free agency after 2023. Olson had a solid debut season with his hometown team (34 homers, 103 RBIs), which soared to 101 wins and another NL East title before falling to the Phillies in the NLDS.
2018 Astros: RHP Gerrit Cole
Acquired in trade with Pirates (Jan. 13, 2018)
Cole was on the cusp of putting it all together when the Astros acquired the right-hander from the Pirates, the club that drafted him first overall in 2011 and developed him through its farm system before he posted a 3.50 ERA over five seasons with Pittsburgh. And did he ever -- he had a 2.88 ERA over 32 starts, leading the Majors with 12.4 strikeouts per nine innings and finishing fifth in AL Cy Young Award voting for the Astros, who lost to the Red Sox in the ALCS.
2017 Cubs: RHP Wade Davis
Acquired in trade with Royals (Dec. 7, 2016)
Fresh off their first World Series title in more than a century, the Cubs sent Jorge Soler to Kansas City in exchange for Davis, who would become their new closer after Aroldis Chapman signed with the Yankees as a free agent. Davis was not as dominant with the Cubs as he was the prior three seasons with the Royals, with whom he won a World Series, but remained one of the best closers in the game -- he finished the ‘17 season with a 2.30 ERA and 32 saves. The Cubs lost to the Dodgers in that fall’s NLCS.
2010 Yankees: CF Curtis Granderson
Acquired in trade with Tigers (Dec. 8, 2009)
This was actually a three-team deal that is now best known for Arizona sending Max Scherzer to Detroit. Meanwhile, the Yankees gave up Ian Kennedy, Phil Coke and Austin Jackson (who had yet to make his MLB debut) to land Grandy, whose strong all-around game netted him 4.4 WAR in 2010, when the Yankees lost in the ALCS. Shortly after acquiring Granderson, the Yankees made a big trade for Braves pitcher Javier Vázquez, who struggled mightily in the Bronx.
2009 Phillies: OF Raul Ibanez
Signed to 3-year, $31.5 million contract (Dec. 12, 2008)
When Pat Burrell became a free agent, the defending champs needed to fill a vacancy in left field and the man they chose went on to earn his only career All-Star selection in 2009. Ibanez, in his age-37 season, posted career highs with an .899 OPS and 34 home runs and then added 13 postseason RBIs as the Phillies returned to the World Series before falling to the Yankees.
2006 White Sox: DH Jim Thome
Acquired in trade with Phillies (Nov. 25, 2005)
Chicago also acquired Vázquez via trade after winning the World Series. But the bigger move was for Thome, who, at 35, was well on his way to the Hall of Fame by that point but had become expendable in Philly, thanks to the emergence of 2005 NL Rookie of the Year Ryan Howard. The White Sox, meanwhile, were faced with the free agencies of both first baseman Paul Konerko and DH Frank Thomas. Ultimately, Konerko returned to pair with Thome, who enjoyed a fantastic debut season in Chicago (1.014 OPS, 42 homers). Despite winning 90 games, however, the club missed the playoffs.
2001 Yankees: RHP Mike Mussina
Signed to 6-year, $88.5 million contract (Dec. 7, 2000)
The two parties knew each other well. Mussina had starred in the AL East with the Orioles from 1991-2000, but despite some excellent postseason performances, never made it to the World Series. Meanwhile, at the time of the signing, the Yankees had three straight championships and four of the past five. Mussina was as-advertised in his Bronx debut (17-11, 3.15 ERA in 228 2/3 innings) and made his first trip to the Fall Classic, but the Yanks fell to the D-backs in seven.
1999 Yankees: RHP Roger Clemens
Acquired in trade with Blue Jays (Feb. 18, 1999)
The 1998 Yankees staked a claim to “best team of all-time” status, going 114-48 in the regular season and 11-2 in the postseason, including a World Series sweep over the Padres. But they weren’t satisfied. In a move that owner George Steinbrenner compared to getting Michael Jordan, New York sent a package including lefty David Wells to Toronto for Clemens, who already owned five Cy Young Awards, including two straight with the Blue Jays. The Rocket actually struggled in ‘99 (4.60 ERA), but contributed to the Yankees’ World Series victory over the Braves.
1993 Blue Jays: DH Paul Molitor
Signed to 3-year, $13 million contact (Dec. 7, 1992)
After winning the 1992 World Series, Toronto swapped one aging, future-Hall of Fame DH (Dave Winfield) for another (Molitor), via free agency. The 36-year-old Molitor was reluctant to leave Milwaukee after spending his first 15 seasons there, but with the Brewers not making a satisfactory offer, Toronto stepped up. Molitor proceeded to make his third straight All-Star team, batting .332 with an MLB-high 211 hits in ‘93, then raked in the postseason. He went 12-for-24 (.500) with six extra-base hits and eight RBIs, earning World Series MVP honors as the Jays claimed their second straight championship.
1987 Mets: OF Kevin McReynolds
Acquired in trade with Padres (Dec. 11, 1986)
Shortly after claiming the franchise's second World Series title, the Mets pulled off an eight-player blockbuster with the Padres to acquire McReynolds. The 26-year-old outfielder had averaged 20 home runs over his first three full seasons with the Padres, though he also added more of a speed element to his game upon arriving in Queens. McReynolds hit a career-high 29 homers in his debut season with the Mets in '87, then racked up 27 home runs and a career-best 21 stolen bases while helping New York return to the postseason in '88. Unfortunately, the Mets would fall in seven games to the Dodgers in the NLCS -- despite a pair of home runs in the series from McReynolds -- and that would prove to be their only trip to the playoffs during the outfielder's initial five-year stint with the club.
1981 Phillies: OF Gary Matthews
Acquired in trade with Braves (March 25, 1981)
It's safe to say the Phillies came out on the winning end of this deal. After winning the 1980 World Series, the Phils traded right-hander Bob Walk -- coming off a rookie season in which he finished seventh in NL Rookie of the Year Award voting -- to the Braves in exchange for Matthews, who had previously won the '73 NL Rookie of the Year Award and was an All-Star in '79. While Walk posted a 4.85 ERA over 45 appearances before being released by Atlanta, Matthews earned a share of NL MVP votes in each of first two seasons in Philadelphia and was named the '83 NLCS MVP before the club ultimately lost to the Orioles in the World Series.
1979 Yankees: RHP Luis Tiant, LHP Tommy John
Signed Tiant to 2-year deal; Signed John to 3-year deal
Though Tiant was just 10 days shy of his 38th birthday when he agreed to join the Yankees, he had still been a serviceable starter for the rival Red Sox in recent years. He had finished in the Top 5 in AL Cy Young Award voting in two of the previous five seasons and was just one year removed from going 13-8 with a 3.31 ERA in 1978. As for John, he was in the midst of his incredible comeback from the procedure that now bears his name. After undergoing what is now known as Tommy John surgery in '75, he returned to the mound in '76 and proceeded to go 47-27 with a 3.05 ERA over the next three seasons with the Dodgers, including finishing as the NL Cy Young runner-up in '77. John also finished as the AL Cy Young runner-up in his debut season in the Bronx, going 21-9 with a 2.96 ERA in '79. John maintained his All-Star form in '80, when he again received a share of Cy Young votes, though the additions of John and Tiant wouldn't help the Yanks win another World Series.
1978 Yankees: RHP Goose Gossage
Signed to 6-year, $3.6 million contract (Nov. 22, 1977)
Coming off three consecutive All-Star appearances with the White Sox and Pirates, Gossage inked a deal to join the reigning champion Yankees following the '77 season. Gossage had just put up a 1.62 ERA over 72 games in his lone season with the Pirates -- but he was just getting started. The future Hall of Famer helped the Yanks win a second straight title in '78, posting a 2.01 ERA and an AL-best 27 saves during the regular season before tossing six shutout innings over three appearances in New York's World Series victory over the Dodgers. Gossage finished in the Top 5 in AL Cy Young voting in three of his six seasons during his initial stint with the Yankees, all while racking up a 2.10 ERA and 150 saves.
1973 Athletics: C Ray Fosse
Acquired in trade with Indians (March 24, 1973)
After knocking off the Reds in seven games in the 1972 World Series, the A's acquired Fosse -- a two-time Gold Glove-winning catcher -- from the Indians. Though Fosse's career was never the same following his infamous home-plate collision with Pete Rose at the '70 All-Star Game, Fosse still proved to be a solid backstop in his first season with Oakland. He helped the A's win a second straight championship in '73, then -- despite hitting just .196 in limited action in '74 -- Fosse came through with a crucial home run in Oakland's World Series-clinching win to secure a third straight title.
1925 Washington Senators: RHP Stan Coveleski
Acquired in trade with Indians (Dec. 12, 1924)
Fresh off winning the 1924 World Series in thrilling fashion with a 12th-inning walk-off in a winner-take-all Game 7, the Senators further solidified their staff by adding Coveleski. Though the future Hall of Famer was coming off a bit of a down year with the Tribe, he had won the AL ERA title with a 2.76 mark in '23. Coveleski averaged 19 wins per season while posting a 2.80 ERA in nine seasons with the Indians from 1916-24. He made an immediate impact with the Senators, adding another ERA title in his debut season with the club after finishing 20-5 with a 2.84 ERA. Coveleski's efforts were enough to earn him a share of AL MVP votes and help the Senators return to the World Series, though they ultimately lost in seven games to the Pirates.