Mike Mayers competely remade himself last season. As I wrote back in October:
Mayers made the transition from starter to reliever over the winter. He was very much a failed starter at the major league level and this was the one path left available to him in order to stay in the majors in 2018. Mayers grabbed the opportunity by its' metaphorical horns and ran with it.
Now, that's not to say that Mayers was a top reliever on the team or anything. He had a lot of good innings, but had a few problems - enough so that he was never really used as a key piece in the pen. He often pitched in losses and threw more than one inning in over 20% of his appearances. The team was 18-32 in his 50 appearances, with Mayers only picking up 1 of those losses himself. In over 1/4 of his appearances, he threw in games in which the Cardinals as a whole gave up 7 or more runs. 10% of his appearances came in games in which the Cardinals gave up double digits. Another 12 of his appearances (24%) came when his team scored at least 7 runs in a game. All in all, 36 of his 50 appearances came when there was a very low leverage index.
Over the last 5 years, the average reliever per 60 games has performed as such (above). I will compare what I have for Mike Mayers' were he to get 60 appearances in the pen. I think Mayers will get his shot and if he succeeds he will get 60 or so chances. However, if his results turn out closer to last year's than his fairly decent peripherals (mentioned later), then he could very well be cut prior to getting 60 chances.
Here is what I have projected for Mike Mayers' 2019 season:
60 games, 60 innings
3.90 ERA, 3.81 FIP, 1.417 WHIP, 2.90 K:BB
9.750 H/9, 8.700 K/9, 3.000 BB/9, 1.050 HR/9
If Mayers were to put up those totals as the long man or as a lower leverage middle reliever in the pen, I don't think that the Cardinals would cut him. I think they have guys with much more potential in the minors, but that those pitchers also could turn out worse than this over the short haul in a small sample at the MLB level out of the pen.
Bottom line is Mayers has to succeed to not be cut because he is out of options. My projections think he'll be fairly successful, but nowhere near dominant.
What can be pointed out to show that things CAN be better than that?!?
I wrote back in October about how Mayers was unlucky last year at times on batted balls in play.
Mayers' 3.95 FIP and xFIP and his 3.69 SIERA [in 2018] lend credence to him being better than his 4.70 ERA would have suggested from this year. Mayers had the distinction of being the 4th least lucky pitcher on the Cardinals by his expected outcomes vs his actual outcomes according to Statcast. Based on the batted ball types against him, he should have allowed a batting average of .253 and a slugging of .411. That'd be an OPS of just .664 on batted balls. Instead, he was torched for a .289 average and .485 slugging, giving him an OPS against of .774 on batted balls. That's 110 points (16.6%) worse than what "should" have happened. Just some horrible batted ball luck at times this year. In fact, he was unlucky enough that out of the 361 pitchers who pitched to at least 200 batters this year, he had the 11th highest difference between his actual wOBA and his expected wOBA (xwOBA) this past season. He's due for quite a regression next year if he can keep his peripherals the same.
If he's going well, his slider can fool people, like Billy Hamilton here (thanks, gifs!):
If I'm not mistaken, Mayers is throwing a curve now (I've heard it described as a "spike curve") that he and Mike Shildt and Mike Maddux believe can be very significant in his development as a reliever. That slider above was relied on this past season, but if he can add another plus breaking pitch, then he could be quite effective.
How/If things go wrong:
Mike Mayers failed as a starter and last year put up an ERA near 5. I don't think that it's very difficult to see what could go wrong.