Every Hot Stove season comes with the potential of blockbuster deals, whether by free agency or trade. But there have been some offseason trades throughout baseball history that have particularly stunned us, catching us by surprise and creating exciting storylines for the upcoming season.
Here's a look at 10 of the most stunning offseason trades in MLB history.
Dec. 3, 2018: Mets trade Jay Bruce, Anthony Swarzak, Gerson Bautista, Justin Dunn and Jarred Kelenic to Mariners for Robinson Cano and Edwin Diaz
The Mariners decided to rebuild after an 89-win season, as general manager Jerry Dipoto determined his roster was not strong enough to compete with American League powerhouses including the Red Sox, Yankees and Astros. Meanwhile, new Mets general manager Brodie Van Wagenen sought impact additions as he inherited a club coming off a disappointing 77-win campaign.
At the center of it all was Cano's massive contract, in which he was still owed $120 million over the remaining half of the 10-year deal he originally signed with Seattle prior to 2014. Cano was also coming off an 80-game suspension after he tested positive for a banned substance, further complicating his future in Seattle. Looking to clear up payroll space for his retooling efforts, Dipoto packaged Cano and Diaz -- the closer coming off a franchise-record 57-save season -- to New York in a deal that netted him both salary relief and a pair of top prospects in the right-hander Dunn and the outfielder Kelenic.
Video: Mets acquire Cano, Diaz in 7-player trade
Dec. 9, 2015: D-backs trade Dansby Swanson, Ender Inciarte and Aaron Blair to Braves for Shelby Miller
Miller was an All-Star with the Braves in 2015, as the 24-year-old right-hander posted a 3.02 ERA in 33 starts and looked to have a bright future ahead of him. But the D-backs made an overwhelming offer, sending Swanson -- the first overall pick in the '15 Draft -- along with speedy center fielder Inciarte and right-hander Blair to Atlanta.
"We wanted to make it painful for [the D-backs] with players that we got back," Braves president of baseball operations John Hart said at the time. "They are players that we think are going to be a big part of our future."
Video: D-backs get Miller from Braves in blockbuster deal
Swanson was the No. 10 prospect in baseball at the time, according to MLB Pipeline. Inciarte was coming off a solid second year in the Majors, hitting .303/.338/.408 with 21 steals for Arizona, while playing a stellar center field with 29 defensive runs saved. Both played key roles in helping the Braves win the National League East last season.
Meanwhile, Miller has been beset with injuries since being traded to Arizona, and when he has been on the mound, he's struggled. In 29 appearances (28 starts) over three seasons with the D-backs, he has a 6.35 ERA. He's only made nine starts since '16.
Nov. 20, 2013: Tigers trade Prince Fielder to Rangers for Ian Kinsler
This deal was a stunner because Fielder, at age 29, had missed just one game in five years, and in two seasons with the Tigers had slashed .295/.387/.491 with 55 home runs. Nevertheless, Detroit dealt him to Texas in what proved to be a good move; Fielder would only have one more full season remaining in his career, with chronic neck injuries leading to his retirement at age 32.
Kinsler was an All-Star in his first season with Detroit, and was productive in his first three years as a Tiger, combining to hit .286/.332/.443 with 56 homers and 39 steals. He missed some time in 2017 due to a hamstring injury, and hit .236/.313/.412 with 22 homers in 139 games. He was traded to the Angels prior to the '18 season, and was traded to the Red Sox last July.
Video: Jason Beck on reaction to the Prince Fielder trade
Nov. 19, 2012: Marlins trade Mark Buehrle, Jose Reyes, Josh Johnson, Emilio Bonifacio and John Buck to Blue Jays for eight players
The Marlins made a big splash on the free agent market following the 2011 season, as they prepared to open Marlins Park the next spring. Miami spent a combined $191 million to sign free agents Buehrle, Reyes and closer Heath Bell. It appeared the franchise was remaking itself, adding those established stars to a club that already featured slugger Giancarlo Stanton. But after a 69-93 season in '12, the Marlins traded Buehrle, Reyes and three other players to Toronto for eight players: Henderson Alvarez, Anthony DeSclafani, Yunel Escobar, Adeiny Hechavarria, Jake Marisnick, Jeff Mathis and Justin Nicolino.
The move represented a stunning reversal for Miami, from a big-spending offseason to build a competitive club, to trading some of their highest-paid players away for young talent. The Marlins have had little success on the field since, finishing no higher than third place in five of six seasons, with a losing record in each one.
Video: Rosenthal breaks down potential blockbuster trade
Jan. 21, 2011: Blue Jays trade Vernon Wells to Angels for Mike Napoli and Juan Rivera
Wells had suffered a series of injuries but bounced back for a strong season in 2010, compiling a 125 OPS+ while hitting 31 homers and driving in 88 runs. The Angels were desperate for an impact bat after missing out on several bids in the free-agent market including Carl Crawford and Adrian Beltre, and ownership issued a directive to bring Wells west.
Wells, a homegrown star with Toronto, was thought to be untradeable -- until he was sent to Anaheim along with $5 million in cash for the powerful Napoli and the veteran outfielder Rivera. Part of the motivation was financial; Wells was due for a raise of nearly $11 million in 2011. But more injuries ultimately prevented Wells from living up to his contract, as he hit just .218 in his debut season with the Halos and played just one more half-season in Anaheim before he was traded again to the Yankees. Wells was out of the Majors within three years of this deal.
Feb. 16, 2004: Rangers trade Alex Rodriguez to Yankees for Alfonso Soriano
This move was stunning not because Rodriguez was moved, but because of which team he ended up with. For weeks, it appeared that Rodriguez was destined for the Red Sox, and Boston was coming off a heartbreaking loss to New York in the American League Championship Series the prior October. Red Sox general manager Theo Epstein and company had a deal in place with Texas, and needed approval from the MLB Players Association to finalize a revised contract for Rodriguez, which would involve him reducing the total amount of his existing $252 million contract, of which $179 million remained.
The MLBPA declined to approve the contract restructuring proposal. Throughout this process, the Yankees -- another club Rodriguez had on his list of preferred trade destinations -- did not show interest in acquiring the superstar shortstop, because New York already had Derek Jeter at short, and ALCS walk-off hero Aaron Boone at third base. But after the Rangers-Red Sox deal was nixed, Boone hurt his knee playing a pick-up basketball game, opening a window for Rodriguez in the Bronx. The Yankees signed him, but while it appeared at the time that New York had once again gotten the better of Boston, the Red Sox defeated the Yankees in that October's ALCS with an epic comeback after being down three games to none, going on to win their first World Series title in 86 years.
Feb. 18, 1999: Blue Jays trade Roger Clemens to Yankees for David Wells, Homer Bush and Graeme Lloyd
Clemens was coming off his second consecutive AL Cy Young season with Toronto, and fifth overall. The right-hander remained his dominant self in his age-35 season, and invoked a clause in his contract in which he was permitted to demand a trade. The Blue Jays tried to strike a deal with the Yankees in mid-December, but New York was unwilling to part with top prospects, and an agreement seemed unlikely.
But in a stunning turn of events, and after Clemens had retracted his trade demand, the two sides reached an agreement that didn't cost New York any top prospects. Instead, the Yankees sent David Wells and a pair of lower-level prospects to Toronto, landing The Rocket in one of the most significant transactions in franchise history.
Video: 2000 ALCS Gm4: Clemens fans 15 in a one-hit shutout
Clemens would end up being instrumental in New York's World Series championships in 1999 and 2000, the last of which marked a three-peat. Wells returned to the organization that originally drafted him in '82, and for whom he pitched the first six seasons of his Major League career. He spent two more seasons with the Blue Jays, posting a 4.47 ERA (111 ERA+), finishing third in AL Cy Young Award voting in 2000.
Dec. 10, 1984: Expos trade Gary Carter to Mets for Hubie Brooks, Mike Fitzgerald, Herm Winningham and Floyd Youmans
Carter was an institution in Canada, and one of the most popular players in Expos history. In 11 seasons with Montreal, he was a seven-time All-Star, won three Gold Glove Awards, and had slashed .272/.345/.461 with 215 home runs. He also hit .429 with four doubles and a pair of homers in Montreal's run to the NL Championship Series in 1981.
The move was stunning, but the Expos were looking to improve at multiple positions after a fifth-place finish in the NL East in '84. Carter would go on to play five seasons for the Mets, being selected to the NL All-Star team four times and finishing third in NL MVP voting in '86, the year he helped New York beat the Red Sox to win the World Series.
Video: Expos Retired Number: No. 8, Gary Carter
April 5, 1972: Expos trade Rusty Staub to Mets for Tim Foli, Mike Jorgensen and Ken Singleton
Staub was known affectionately as "Le Grand Orange," and became immensely popular in Montreal after being traded to the Expos by the Astros in 1969. He performed well on the field -- hitting .296/.404/.501 with 78 homers in three seasons, in each of which he was an All-Star -- and endeared himself to the fans by learning to speak French.
"I felt I should be able to communicate with the people of Montreal in their own language," he told Sports Illustrated in '70. "After all, they were interested in baseball. I thought I should be interested enough in them to learn how to converse with them."
Video: Expos Retired Number: No. 10, Rusty Staub
The trade was a shock to the baseball community in Montreal, and Staub went on to spend four seasons with the Mets and four with the Tigers before Detroit traded him back to Montreal in '79. His second stint with the franchise was brief, however -- he only played 38 games for the Expos before being traded the following March to the Rangers.
Dec. 9, 1965: Reds trade Frank Robinson to Orioles for Jack Baldschun, Milt Pappas and Dick Simpson
Robinson was a tremendous talent, and had proven it with Cincinnati by hitting .303/.389/.554 with 324 home runs over 10 seasons with the club. He was the 1956 NL Rookie of the Year, and the '61 NL MVP. Yet Reds general manager Bill DeWitt said the future Hall of Famer had reached his peak by that point, and sent him to Baltimore following the '65 season.
The centerpiece in the return for Robinson was Pappas, a two-time All-Star right-hander with a 3.24 ERA in nine seasons with the Orioles. He only spent two and a half seasons with Cincinnati, posting a 4.04 ERA in 82 appearances (75 starts) before being traded to the Braves in June of '68.
Video: Orioles Legends Series: Frank Robinson
Meanwhile, Robinson went on to put up even better numbers in six seasons with Baltimore, slashing .300/.401/.543 with 179 homers, becoming the first player to win the MVP Award in each league by doing so in his first AL season with the Orioles in '66. That year, he also won the Triple Crown and led Baltimore to a World Series championship.
Manny Randhawa is a reporter for MLB.com based in Denver. Follow him on Twitter at @MannyOnMLB.