On July 31 of last year, the White Sox thought that they had acquired the piece that would get them back to the World Series. They sent four prospects (Clayton Richard, Aaron Preda, Adam Russell and Dexter Carter) to San Diego for ace Jake Peavy, whom they thought was worth the compensation even though he was an injury risk.

But that risk just became a reality.

The Sox placed Peavy on the 15-day disabled list with a detached right latissimus muscle. The Chicago Sun Times reports that he’ll see the renowned Dr. James Andrews over the All-Star break and that he could miss the rest of the season.

The injury is obviously a huge blow for the White Sox, who currently sit just one game back of the Tigers in the AL Central. Peavy certainly hasn’t been his dominant self this season (7-6, 4.63 ERA, 1.23 WHIP, 93 strikeouts), but don’t forget he missed virtually all of 2009 with an ankle injury and his ERA number was likely to drop as he got more familiar with the American League.

The other frightening aspect of this injury is that Peavy’s career could be done. He has a detached muscle in his back; it’s not like he jammed his finger. He’ll be in good hands with Dr. Andrews, but you never know how a player will respond to an injury like this once he’s ready to get back on the field again.

If the worst thing that happens is he misses the rest of the season, then the Sox should consider themselves fortunate.