The Fight for the Fifth Spot in the Diamondbacks Rotation: An Alternative Approach

A few nights ago I was watching the Tigers on MLB Network, and the broadcast had an in-game interview with Jim Leyland. Like Kirk Gibson, the Tigers skipper is not a particularly great interview, but he spoke about Detroit's own competition for the 5th starter, and it piqued my interest. To paraphrase Leyland, he said that the decision between Rick Porcello and Drew Smyly wasn't being approached by the coaching staff as a competition, but instead a chance to let both pitch and see who would be able to fit better for the club.

On the surface, like most coach speak, this is fairly bland and inane. But as the innings went on my mind wandered, and I began to wonder if there might be more to it.

The Background

Let's throw out the usual approach, first of all. Yes, normally you'd want to just let the players lay it out there, and pick the best, not just in the Spring but who also is projecting to be the best. We're going to assume that our three prime candidates, Patrick Corbin, Tyler Skaggs, and Randall Delgado, are going to perform nearly the same. The reason for this is we want to analyze what each of these pitcher might bring to a rotation as a whole. In other words, we're looking at the rotation as a portfolio, not as independent assets.

The First Four

Before we can look at what candidates might bring, we need to look at what the likely 4 other starters already have brought. In doing this we might be able to determine not only strengths, but weakness as well.

All stats provided by Fangraphs.

None of this should be shocking, but we're looking at a rotation with 3 fly-ball pitchers and a ground-ball pitcher¹. None are flamethrowers, since all 4 hung around 90 miles per hour on their fastball. Even without high heat, though, we have a pitcher in Ian Kennedy who is a borderline power pitcher, and another, in McCarthy, who pitches more to contact. Three of the four are better than average at avoiding free passes, though Cahill is worse than average. And three of the four rely overwhelmingly on their fastball, with McCarthy being the exception.

If we were going to break each down to a set of soundbite characteristics:

• Kennedy is a high strikeout, low walk, low ground-ball, heavy fastball pitcher.
• Cahill is a low strikeout, high walk, high ground-ball, heavy fastball pitcher.
• McCarthy is a low² strikeout, low walk, low ground-ball, light fastball pitcher.
• Miley is a a low strikeout, low walk, average ground-ball, heavy fastball pitcher.

So only one of the 4 is heavy on strikeouts, only one is heavy on the ground-balls, and only one doesn't rely on his fastball well above the average rate³.

The Competitors

If one of the potential fifth starters was either a strikeout or ground-ball pitcher, they might have the inside edge. Of course, if this theoretical player was an effective strikeout pitcher, he probably wouldn't be battling for only the 5th spot. Irregardless! Another table:

The above table uses 2012 numbers only for everyone but Collmenter since they only had major league numbers for last year. I used Collmenter's career numbers to try get a better idea of what to expect. If we apply the same breakdown as above we get:

• Corbin is a low strikeout, low walk, average ground-ball, heavy fastball pitcher.
• Skaggs is a low strikeout, high walk, low ground-ball, heavy fastball pitcher.
• Delgado is an above average strikeout, high walk, high ground-ball, heavy fastball pitcher.
• Collmenter is a low strikeout, low walk, low ground-ball, heavy fastball pitcher.

Okay, What Does It All Mean?

At first blush it would seem that Delgado would bring the most difference to the table, in that he'd bring the heat and induce ground-balls. The downside to this, and this where reality creeps in, is that Delgado probably will be behind both Corbin and Skaggs in overall talent. Sure, he has a higher average velocity for the fastball, but what is he doing with it? He's not racking up a ton of strikeouts, that's for sure. And when you look at the actually quality of his starts, it's not particularly inspiring. The walks are particularly worrying.

The good news is that he, like his competitors, are all young. We have a basic idea of what they've shown so far, and where their talent might project towards, but Delgado still might develop further and be more productive in the future.

Collmenter has had previous chances to show his stuff as a starter, and it's been a mixed result. He's not going to walk people, which is good, but he is an extreme fly ball pitcher, which might continue to be toxic in Chase Field.

That leaves us with Corbin and Skaggs. The latter had a rougher time last year, and certainly might settle down. He got himself into trouble last year by walking too many batters, and relying on his curveball too much. I'd expect him to lower his BB/9, but it probably won't go down drastically as he showed a tendency to walk batters whilst in the minors.

Corbin, on the other hand, should add a little more balance to the rotation without the free base problem. He's more of an average ground-ball pitcher, but that should help balance out a rotation that largely gives up fly balls in a fly ball paradise. He showed decent poise last year, and probably has the inside track this Spring.

Building a rotation isn't exactly a science, though there's should be an obvious desire to fill it with the best available pitchers. There's also something to be said for trying to select players who will succeed in the environment provided. Don't have ground-ball pitchers if your infield doesn't have range, don't have fly ball pitchers if your outfielders don't have range (or if you're in a homer friendly park).

I think there's a case to be made that the current front-runner, Patrick Corbin, will both be the best choice but also bring a little more balance to the rotation, both in being a lefty, but also in being more of a ground-ball pitcher who can also get strikeouts.

Perhaps most importantly, though, is that the D-backs have some options. If Corbin doesn't work out, then there's Skaggs, Delgado, Collmenter, and Charles Brewer all potentially able. And, oh yeah, Daniel Hudson is expected back around the All-Star Game. That's a lot of pitching for only one or two spots, but it's not a bad problem to have.

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1. I'll admit that I was surprised that McCarthy wasn't more of a ground-ball pitcher, given the hype, but I'm not the only one surprised.

2. Low being 'below average.'

3. I'm using the past 3 years composite as the average.