I don't know how to tell you this, so I'm just going to be as frank as possible; Tanner Scheppers has not been very good this year.
I know, it's shocking stuff. I had to double-check the numbers myself.
Let's look at the macro first. Tanner's ERA of 9.82 is currently the worst among starters in MLB. Well, techinically. See, the leaderboards haven't refreshed yet, so it's possible someone jumps him for that honor, but here's the thing: his ERA was the worst in the league BEFORE he gave up six runs in 2.1 innings today.
Now, we all know ERA doesn't tell the whole story of a pitcher's performance, but having the worst in the league after three weeks generally isn't the kind of thing you build a resume around. Both FIP (6.26) and xFIP (5.02) suggest there's some bad luck to his ERA, and that with time that number should come downwards. In general, that's comforting, but they suggest that it's going to come down to just bad, whereas now it's awful.
In Three True Outcome terms, Tanner's doing an OK job. He's striking out about 15 percent of all batters faced, which isn't good (103rd out of 115 qualified pitchers) but he's only walking 8.7 percent of all batters faced (84 out of 115). That means he strikes out 1.62 times as many batters as he walks- that's pretty bad, but it's not as epically terrible as his ERA would make him seem.
The real issue with Scheppers this year has been the hits. Batters are hitting .321 off Scheppers by my count after today- that's about the tenth worst rate in the league. You've heard me say, many times, that a high groundball rate is a very desirable thing- even though groundballs turn into hits more often than anything other than liners, they rarely turn into extra-base hits, and quite often turn into double plays to balance everything out. Tanner's inducing groundballs at a rate of 54.5% this season; good for 18th in the league (maybe he could learn a thing or two from his pal Robbie Ross, leading the league currently at 72 percent).
All told, when batters make contact against Scheppers (and they do quite a bit, remember the 14.5 percent strikeout rate) they're successfully turning into hits at a .359 rate (that's BABiP). That's 14th highest in the league. BABiP is still a mysterious beast, but a good rule of thumb is taking a pitcher's line drive rate and adding .12 to it to approximate what a pitchers BABiP “should” be. Scheppers' LD % is 14.0 percent; in other words, a BABiP of .260 wouldn't look out of place. Which means a third of all hits against Scheppers seem to be the effects of bad luck.
There's also the fact that there's two Tanners; the one that's pitched 2.1 innings and allowed 18 earned runs, and the one that's pitched 16 innings and allowed two runs. Tanner's had two innings with six runs (one of which he only got one out in), another with five, and two other with one. Other than those, he's thrown up zeros; which means every single inning has involved throwing up somehow with Tanner this year.
The team knows Tanner is a talented pitcher, and that he has the athleticism, build, and makeup to pitch as a starter. What he's lacking, four starts in, is results. The question is, with Matt Harrison coming back and Robbie Ross doing nothing to make it seem like he doesn't belong in the rotation (yet), can the team afford to let Scheppers work out whatever is causing that one evil inning in the majors and in the rotation, or does he need to move back to the bullpen (which has some question to it, because how is his confidence going to be after a month of abject failure as a starter?) or as a starter in Round Rock?
Joseph Ursery's pretty sure everyone could learn something from Robbie Ross. You can learn any number of things by following Joseph on twitter, via @thejoeursery.