Colon is insurance for the Sox, as Curt Schilling status to pitch this season remains a serious question mark. Colon has suffered through two injury-riddled seasons since he won the Cy Young Award as a 20-game winner with the Angels in 2005. It's also a minor league deal, so Colon has to prove he's healthy and still has something left.
Here are Colon's lifetime stats: http://www.baseball-reference.com/c/colonba01.shtml
I'll always remember Colon from the time the Red Sox were trying to get him in 2002 from Cleveland, but the Red Sox would not give up promising lefty Casey Fossum (remember him?) to complete the deal. Fossum eventually was traded in 2003 to Arizona in the trade for Curt Schilling, and now the Red Sox pick up Colon as a possible replacement for: Curt Schilling.
Talk about going full circle.