Josh Beckett would take the Florida Marlins to the 2003 World Series Championship and would win the World Series MVP along the way. 

Mo Vaughn was one of the ultimate one-dimensional power guys, but if that is going to be your skill, you might as well be good at that.  Vaughn was exceptional in that skill.

A member of the Boston Red Sox for all but his final season (2002), John Valentin was one of the better defensive players in Red Sox history.

Prior to being traded to the Red Sox, Joe Cronin was the on-field leader of the Washington Senators, and he was the runner-up for the MVP in 1933.  Cronin was dealt to Boston, and the Sox coveted him not just for his bat, but for his mind, as he became their Player/Manager.