I understand that in some leagues, the number of rosterable pitchers is greater than the number of available roster spots, but if in your league, you're still messing around with a middling Jeremy Guthrie or Jose Quintana type, you might want to go ahead and take a flier on pitching prospect Michael Wacha even though we don't know just how long he'll stick with the Cardinals.
The 19th overall pick in last year's draft isn't quite on the level of a Kevin Gausman in terms of upside, but he's pretty close. And he's certainly a quick study. In his first full season of professional baseball, he has a 2.05 ERA and 0.95 WHIP over nine starts in the hitter-friendly Pacific Coast League, and he was even more dominant in spring training, striking out 15 without allowing an earned run in 11 2/3 innings.
Given all the injuries to their pitching staff, the Cardinals have had plenty of opportunities to bring up Wacha before now, but now that they've finally broken the seal on him and kicked off the arbitration clock, I'd guess he's more likely to stick around than a low-upside Tyler Lyons, provided he meets his end of the bargain.