Jake Westbrook always looks like he's pitching with a lower back strain—he's got the least impressive follow-through of anyone in baseball, non-Wakefield division—so whether this is a "genuine" injury or the kind of injury teams discover through inductive reasoning, the St. Louis Cardinals are certainly in the right to put him on the disabled list. But his replacement, at least for Monday's start, was a surprise: Tyler Lyons, and not Michael Wacha or Carlos Martinez.
Lyons has been impressive in Memphis, just like last year—he's struck out 84 batters and walked 19 in 98 innings—but the Cardinals' unwillingness to leave Wacha in the rotation is among the season's weirder subplots. Lyons is a useful sixth starter, and I'm glad to see him get an extended major league audition, but Michael Wacha is probably a major part of 2014's rotation, as well as the High Upside play this year. In the bullpen he's another guy who isn't Trevor Rosenthal, which is good, but also constrained by how important he is to the Cardinals' rotation in the immediate future. I can see becoming dependent on one of those guys—Carlos Martinez, maybe—but I'm not sure how both of them will kick around the bullpen without one of them—Carlos Martinez, probably—vanishing into the ether again.
One way of looking at it that makes sense to me: this start is a chance to stretch Wacha out and back away from their persistent, unconvincing threats to get him into back-to-back games any day now, just you wait and see, just like a real reliever.