01:00 AM EST on Sunday, April 2, 2006

Baseball is an integrated game of offense and defense. And defense includes not just the fielders behind the pitchers, but the pitchers themselves.

Red Sox general manager Theo Epstein frequently speaks of "run differential" -- the difference between the number of runs scored by a team and the number of runs it allows. If the differential is high enough, victories generally follow.

The 2005 Red Sox were good when it came to scoring runs, not so good at preventing them. To fix that, the Sox traded for or signed four new pitchers, with Josh Beckett being the key acquisition. They also sacrificed offense at some positions -- shortstop, most notably -- in an attempt to tighten a defense that was, at times, pretty porous in 2005.

Journal sports writer Steven Krasner analyzes how the Sox look heading into 2006.