Crawford's legs make him an impact player on both sides of the ball. He has the ability to find the gaps and hit his share of longballs, even though he'll likely never be a slugger.
He has played 1,235 games in the Majors, hitting .296 with 215 doubles, 105 triples, 104 homers, 592 RBIs and 409 stolen bases. In 78 career regular-season games at Fenway Park, Crawford owns a .275 average with 24 doubles, 35 runs scored and 26 stolen bases.
After winning the World Series in 2004 and again in 2007, the Red Sox advanced to Game 7 of the American League Championship Series in '08, but were ousted by Crawford's Rays.
The Red Sox had a slight downturn the last two years, being swept in the Division Series by the Angels in 2009 and missing the postseason in 2010 when their injury-riddled team recorded 89 wins.
But now, Boston has made a strong push to play deep into October again. Though Epstein has never been shy about making moves during the Hot Stove season, these two transactions probably mark his most dramatic winter splash since the acquisitions of Curt Schilling and Keith Foulke seven years ago fueled the '04 title run.
With their offense more than solidified, Epstein's main focus now will be to solidify a bullpen that was Boston's glaring weakness in 2010.
Ian Browne is a reporter for MLB.com. Read his blog,
Brownie Points, and follow him on Twitter
@IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.