Masterson a perfect fit for Cards

Starter Justin Masterson's BABIP of .350 is the fourth-highest in baseball this season. AP Photo/Mark Duncan

A few days ago, the Cardinals' rotation was in trouble. When starter Michael Wacha went on the DL with a stress reaction in his throwing shoulder, it was difficult to know what to expect. Stress reactions are fairly uncommon, so we had few prior examples to use to estimate when he might return. The Cardinals might have more starter depth in their organization than any other team in baseball, but no team has the depth to replace a pitcher of Wacha's caliber. With less than a year of experience in the majors, Wacha had already become the second ace of the Cardinals' staff. His 2.79 ERA this season would be the 12th best in the NL if he had enough innings to qualify for the ERA title.

It has been more than a month since Wacha last threw a pitch. As the uncertainty of his status lingered late into July, it seemed the Cardinals would have to add a pitcher at the deadline. Speculation had them tied to David Price and Jon Lester, two of the best starters believed to be available. With their loaded farm system, the Cardinals would be one of the few teams with the prospects to acquire those elite players. And given that the Cardinals trail the Brewers and the Pirates in the NL Central, many believed St. Louis needed to make a major upgrade to secure its ticket to the postseason.

But the Cardinals did not trade for one of those elite starters. Instead, they traded for Justin Masterson and John Lackey.