Taking a Closer Look at Starter/Reliever Pitchers

This should go without saying, but fantasy owners have to be careful with starting pitchers who previously spent time in the bullpen. As we all know, good relievers aren’t all cut out for the starting rotation. The ability to go hard for short bursts allows relievers to cover up deficiencies that prevent them from being starters, with the lack of a third, or even second, pitch being a prime example. But sometimes it is easy to forget that a pitcher spent time in the bullpen when looking at his player page at the end of the season.

Enter Yusmeiro Petit. If you were to ignore or simply overlook the fact that Petit has appeared in 37 games but only started 10, you might overvalue him when doing your fantasy prep next March. What really jumps off his player page is the more than one run difference between his ERA (3.64) and his SIERA (2.51). That super low SIERA would seem to be backed up by a 24.1% K-BB%, which is further backed up by a 12.3% SwStr% and 69.6% F-Strike%. Those are damn near Chris Sale-level numbers. His league average BABIP is further evidence one could use to say the SIERA is legit. His below average LOB% (66.7%) also seems to suggest positive regression given his below average home run per fly ball rate (8.1%). Personally, I like that his OPS allowed on balls on play is 21% better than league average. That tells me he’s good at limiting hard contact.

The problem is that Petit’s best work came in the pen. The one exception is his walks. His walk rate in the pen is 5.9%, and it’s an even better 3% as a starter. But all the other good things mentioned above range from a little worse to quite a bit worse as a starter. He has the same number of strikeouts as a starter and as a reliever except that he has faced 43 more batters as a starter. He has allowed nine home runs as a starter compared to one as a reliever despite only throwing 8.1 IP more as a starter. As for limiting hard contact, his ISO allowed as a reliever is .069 compared to .193 as a starter.

Again, it’s not exactly breaking news that pitchers struggle more as starters than they do out of the pen. This is just a friendly reminder to break it down when you see a pitcher who split his time between the two roles. And it should also be said that Petit is still an interesting sleeper name for next season, he’s just not quite the super-duper breakout stud his player page might initially lead you to believe he is.

A quick perusal of the xFIP leaderboard shows that Carlos Carrasco, Alex Wood and Josh Tomlin are the other most successful starter/reliever pitchers of the year. Carrasco’s success has been equally driven by his work out of the pen and as a starter. His OPS allowed is 33% better than league average as a starter and only 35% better than league average as a reliever. There’s also no need to fade Wood because even though he has been more successful out of the pen, about 90% of Wood’s work has come as a starter. His season long line is a useful tool when evaluating him as a starter going forward.

Tomlin is like Petit in that he looks like a really good breakout candidate for next season. Tomlin’s ERA (4.76) is also more than a run higher than his SIERA (3.27). Tomlin also has a healthy K-BB% (17.9%) and an above average, but not elite, SwStr% (9.4%) and F-Strike% (67.6%). The good news for Tomlin is that he’s more comparable to Carrasco than Petit in that he hasn’t been worse as a starter. In fact, he has actually been much better as a starter with an OPS allowed of .759 as opposed to .926 as a reliever. And he’s more comparable to Wood than Petit in that the large majority of Tomlin’s work has been as a starter. So it’s not always as simple as fading a pitcher whose season long line looks good but includes time as a reliever. Make sure you take the time to break it down and see what’s really going on.