The Hangover: So When Does Miguel Diaz Head To The Rotation?

(Patrick Brewer did a good comparison of Miguel Diaz and Luis Perdomo the other day over at EVT, but what the heck. I’ve got a streak to protect here.)

It’s really easy to compare Luis Perdomo and Miguel Diaz. Both are right handers of similar size, both are Rule 5 picks plucked out of A-ball, and both struggled big time upon entering the major leagues. Take a look at how similar Perdomo and Diaz performed through May of their rookie seasons:

Player Innings Hits ERA HR/9 K% BB%
Perdomo 26 47 10.04 1.4 14.8 12.0
Diaz 22 2/3 21 7.15 2.0 16.0 12.0

Perdomo was actually worse, somehow, but if you just focus on the peripherals, they’re really similar. Let’s back up a bit further and compare these guys in the minors:

Player Innings Start % ERA HR/9 K% BB%
Perdomo 316 92.4 4.10 0.5 19.4 6.7
Diaz 236 48.6 3.61 0.4 22.0 8.9

The numbers are close again. Both guys suppressed homers while posting solid strikeout and walk numbers. Important to note that Perdomo was almost exclusively a starter in the minors, whereas only about half of Diaz’s appearances came as a starter. Also, Perdomo was pushed a bit more rapidly through the minors, so more of his performance came against slightly tougher competition. Still, similar profile.

Anyway, last year, when Perdomo was in the midst of that terrible early struggle, the Padres did something crazy. They moved him into the rotation. That’s not supposed to work. Relieving is, simply put, easier than starting. Pitchers tend to post better numbers in a relief role, mostly for obvious reasons: it’s easier to go one inning at a time, velocity generally jumps up, there’s no multiple-times-through-order penalty. It’s just a cushier gig, and moving a guy who can’t cut it in the bullpen to the rotation is almost always doomed from the start.

But Perdomo broke through, at least to a degree. As a starter last year, in 117 innings, Perdomo pitched to a 4.85 ERA with a 2.7 strikeout-to-walk ratio. Baby steps . . . remember his numbers from April and May. The surface stats don’t show it, but Perdomo has been even better this year. His strikeout rate is up five percent, his walk rate has stayed the same, and his DRA is down over a point. Not saying Perdomo is out of the woods yet, but he’s at least someone you’re paying attention to right now. You don’t have to squint to see him sticking around the Padres rotation for a while.

So, will the Padres try the same thing with Diaz?

It’s probably not a great idea, really, for the same reasons we discussed above with Perdomo. Plus, Diaz profiles more as a reliever long term, though some still see starting potential (the fact that he’s gone to his changeup nearly 20 percent of the time, with solid results, is a good sign). But I wouldn’t put it out of question. There’s not a ton of room is the rotation right now, and Trevor Cahill and Jered Weaver could return soon. On the other hand, Jarred Cosart has to be on thin ice, Weaver’s a major question mark to last, and guys like Cahill, Clayton Richard, and Jhoulys Chacin are obvious deadline trade candidates.

If a spot opens up sometime this summer, it wouldn’t be surprising to at least see the Padres give Diaz a shot at cracking the rotation. It’s one of the benefits of *whispers* tanking, in that you can throw stuff at the wall and see what sticks. If Diaz takes to starting, great. You’ve pulled off Perdomo 2.0. If he doesn’t, well, it just helps the Beer* Run. When winning the games isn’t necessarily the priority, moving a struggling reliever into the rotation is an option that other teams don’t dare try. The Padres made it work once, so maybe they’ll test their luck again.

*As an aside, it’s unclear that Seth Beer is going to go No. 1 overall in next year’s draft. It seems a lot more likely that he falls a bit, really. But that’s for another day.

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  • Drakos

    Good stuff (as usual). It got me wondering about how many innings each had pitched the year before they joined the Padres. Turns out that Perdomo threw about 30 innings more so his workload with the Padres was only an increase of 20 innings. I wonder if the Padres will keep Diaz in the pen longer just so his innings increase isn’t too large.

    • Right on, great point. That could very well be something they’re considering if they make the switch.