Since Chris Carpenter's arm finally threw its last Major League pitch in 2012, Adam Wainwright has been the unquestioned ace of the staff. I mean, you could argue he was the ace before that moment (and I would agree) but after Carp was gone, there was no argument. Over the last ten years, 2006 to 2015, here are the top 10 best individual seasons from Cardinals starting pitchers, according to fWAR:
The list is dominated by Carp and Waino, with Joel Pineiro looking as out of place as ever. Maybe the Cardinals shouldn't expect Wainwright to pick up mostly where he left off in 2014, where he was worth nearly five wins over a replacement player, but they shouldn't expect him to simply fall off either. The projections agree, as Fangraphs' depth charts page, which averages Zips and Steamer projections of rate stats along with writer-maintained playing time projections, has him at 4.0 WAR over 206 IP, which isn't as good as 2015 or 2014 but is still a strong total, placing 20th best of all pitchers in the Majors.
That 4.0 projected WAR total is first among Redbird pitchers, which shouldn't be much of a surprise despite a strong staff. The FIP of 3.30 is very nearly first, but was beat out by just one point by none other than El Gallo himself, Carlos Martinez. Yep, among starters on a rate basis, Carlos Martinez is the projected best Cardinals pitcher going into 2016. Of course, Carlos is projected for 47 less innings, and pitching more innings is certainly a skill, so Wainwright is still projected as most valuable overall. It's still encouraging however, to see such a strong projection for Martinez on a rate basis.
Remember too that this isn't just projection; in 2015 Carlos Martinez actually threw more innings and pitched to a lower FIP than he's projected to in 2016, so the projections are indeed predicting a little bit of regression rather than a break-out. The downside to that projection is the light total of 159 innings. That number is low for two reasons: (1) his injury at the end of the regular season and (2) his light innings totals in the past. The first is certainly understandable; recent prior injuries are the best predictors of future injuries.
The second is a little more contextual. Sure, Carlos has had light innings totals in the past, but before 2015, the Cardinals have been very careful in ramping up his inning totals. The team talked about innings limits before and throughout 2015, but ended up basically treating him like a normal pitcher. Some might say the unrestricted usage in 2015 caused the injury late in the year, but pitching injuries simply aren't that easy to predict. Maybe El Gallo's arm just can't handle a full starter's load of innings, but it's easy at this point just to assume a coincidence. Pitchers break all the time, and the person who figures out the specifics as to why will make a lot of money in baseball.
Carlos did manage to go deeper into games than average in 2015. His average start lasted just over six innings (6.02) whereas the league average was 5.81. However, even in this, the age of every team having several strong relievers, what separates a strong pitcher from an ace, is consistently going late into the game. For instance, from 2014 to 2015 Waino averaged 7.1 innings per outing. That's an extra 4 outs over the average pitcher per start, which is nothing to sneeze at. Over the course of the regular season that's more than 40 extra innings.
That's where Carlos needs to improve at this point. At 34, Adam certainly isn't getting any younger, and he won't be an ace forever. Due to his incredible stuff and strong numbers on a rate basis, he has the best shot to take the mantle. With Wainwright and Molina's tutelage in all the mental and physiological aspects of pitching an MLB game, I think he's going to do it.