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David Phelps: Another Marlins Pitcher on the Rise

After writing about Marlins’ hurler Tom Koehler last week, the continued dominance of his teammate, David Phelps, has forced me to turn my attention to him. How good is this guy? What is his fantasy value?

Miami Marlins v Pittsburgh Pirates
Is this the next Danny Duffy?
Photo by Justin K. Aller/Getty Images

You may have read my post last week wherein I discussed the suddenly more interesting Marlins pitcher, Tom Koehler. He successfully transitioned from very boring streaming-only to ownable in most leagues. While Koehler quietly improved his offerings and increased his strikeout rate, his teammate, David Phelps has been pulling a Danny Duffy, taking elite performance in a bullpen role and carrying it over to the rotation. Here at Fake Teams, Ray has discussed this breakout candidate already. I’m hoping to add some more fuel to that fire.

Here are Phelps’ numbers as a starter and as a reliever this season.

Starter 20.2 1.31 1.02 32.5% 8.8% 2.9 2.79 10.4% 93.4 51.1% 0.0%
Reliever 54.1 2.65 1.14 31.5% 10.1% 2.83 3.33 9.7% 93.8 42.7% 10.6%

His numbers in both roles are magnificent. His K% is even better as a starter than as a reliever. Ditto his WHIP, walk rate, GB%, and xFIP. His numbers as a starter are skewed by an absurd 99% strand rate and 0.267 BABIP. That is just crazy luck that will eventually even out. Nonetheless, he has been stellar overall and has even maintained much of his velocity as a starter, only dropping from half a mph.

Looking at his individual pitches, his four seam, cutter, and curve all have above average-to-elite swinging strike rates. His two-seam and curve are great at generating ground balls. Keep in mind that these swinging strike rates are for the whole season. They are likely lower actually higher as a starter, since his overall swinging strike rate has fallen risen from 9.6 to 10.4%! I was clearly not expecting that. Wow!

He has three different fastballs and a curve. They are all good at what they do. What is missing? Well, you’ll notice I didn’t mention either his slider or his change-up. His slider is just awful (5.3% swinging strike rate) and while his change-up has been very good in small samples (18.8% SwStr%), he has no trust in the pitch (he’s thrown 16 all season). The slider isn’t really needed for anything, since he already has two good breaking pitches (cutter, curve), so that’s not a problem.

However, the lack of trust in the change-up is a big problem. Why? Take a gander at this nice little table of his lefty-righty splits.

v LHB 30.2 25.4% 15.7% 1.53 4.78 4.34
v RHB 44.1 37.0% 4.9% 0.81 1.52 2.38

How about those splits?

I couldn’t get his splits as a starter vs reliever against LHB and RHB, so those are his full season numbers, but they tell an ugly story. In order to keep pitching at this level as a starter, he needs to improve against lefties. He has that changeup, if he can just get more comfortable with it. He obviously didn’t need it as a reliever, so maybe that’s why he didn’t throw it much, but he needs to establish it now. To his credit, he has upped his change-up usage since he became a starter in August.

It is still only at about 5%, but it’s something. Take a look at the chart for just lefty hitters.

He’s up to 10% against lefties now. He’s also dropped the sinker usage big time in favor of his great four seam. The fact that he’s adjusting to starting is a very good sign.

I was able, thanks to Brooks Baseball, to find his slugging and ISO by month against lefties. They both bounce around quite a bit, but his August (starting) ISO and slugging are basically right at his season-long averages for each stat. His August ISO against is 0.194 and his August slugging against is 0.452. So at least he hasn’t really gotten any worse against lefties as a starter than he was in relief.

Let’s wrap this up. We’ve all got families and friends to go home to. Well, if you don’t, then you’ll always have me as a platonic, Internet-only, distant friend. Phelps is looking very promising early on in his starting career in Miami. He’s already 28, so he isn’t some hot prospect, but he’s looking like a guy worth a roster spot in all leagues at this point. If he can continue to improve against lefties and somehow keep up his ridiculous four seam whiff rate, he could be a top-20 pitcher the rest of the way. Tschus!