However, Red Sox president of baseball operations Dave Dombrowski struck early this offseason, enabling him to pick and choose and work from a position of strength.
"I'm definitely sure they're not finished yet," Red Sox shortstop Xander Bogaerts said of his front office. "Who knows what else they're going to do?"
After finishing in last place in the American League East the past two seasons, Boston is highly motivated to make whatever moves need to be made to get back into contention. There could be some opportunities in Nashville to further upgrade the club.
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With Kimbrel in the fold, the bullpen looks far better than it did going into the offseason. Koji Uehara goes from closer to setup man. The underrated Junichi Tazawa moves from the eighth inning to the seventh. But you can never have enough depth in the bullpen, and Dombrowski might pursue another piece or two.
The position-player core is fairly well set, with veterans David Ortiz and Dustin Pedroia leading a group that also includes blossoming young players Bogaerts, Mookie Betts and Blake Swihart.
Dombrowski could be tempted to pursue another established bat in the outfield. The Red Sox are confident in what Betts will produce at the plate, but Jackie Bradley Jr. and Rusney Castillo are still unproven from an offensive standpoint.
Considering the haul he dealt to San Diego for Kimbrel, Dombrowski might also look to use some of his surplus to acquire some prospects.
Boston has several starting pitchers who could be appealing to other teams, including Clay Buchholz, Joe Kelly, Wade Miley and Henry Owens.
MLB.com and MLB Network will have wall-to-wall coverage of the 2015 Winter Meetings from the Opryland Hotel in Nashville, with the Network launching 35 hours of live Winter Meetings coverage on Sunday at 8 p.m. ET. Fans can also catch live streaming of all news conferences and manager availability on MLB.com, as well as the announcement of the Hall of Fame Pre-Integration Era Committee inductees on Monday at 11 a.m. and the Rule 5 Draft on Dec. 10 at 10 a.m.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.