Stats for this post were pulled prior to yesterday's games, in which both Nola and Martinez pitched. My opinion of either player has not changed, although another rough start from Martinez may have lowered the price and pushed the needle towards "buy".
If I wanted to be lazy, I could point you to his 2.53 xFIP (3rd in baseball behind only Kershaw and Syndergaard) and just leave it at that. I won't do that, though. Let's take a look at what's driving that number:
He's 14th in baseball in K% and 9th in BB%; only the aforementioned Kershaw and Syndergaard best him in both categories. He's also 7th in GB%, putting him once again in the elite company of Kershaw and Syndergaard as the only pitchers in the top 15 in K%, BB%, and GB%. Pitchers with that combo are rarely unsuccessful. The lone flaw in his "Holy Quaternity" stats is his lackluster pop-up rate; only 0.6% of his batted balls are pop-ups. That flaw is easily forgiven for a pitcher with his elite stats in the other three.
His K and BB rates are driven by plus numbers in SwStr% and F-Strike%. He's using his curveball mostly for whiffs and his fastball to get ahead. Both pitches get groundballs at well
I was asked recently if I think Nola can continue to excel with only one good pitch (the curve). My opinion is that it's not just one good pitch; it's two good pitches and a great one. His changeup is getting good whiffs, his sinker is getting a ton of looking strikes (and grounders), and his curve is great by absolutely any measure. He also has elite command.
There has been a significant amount of coverage of Nola on FanGraphs, all of which was excellent (as FanGraphs usually is). Here are some links for further reading:
Aaron Nola's Sinker and the Looking Strike by Alex Chamberlain
Aaron Nola Has Baseball's Best Curveball by Jeff Sullivan
The Phillies are Curveballing Their Way Into the Future by August Fagerstrom
The Change: Early Starting Pitching Omnibus by Eno Sarris (contains sections on many different pitchers; scroll down to the section labeled Aaron Nola)
An Obligatory Look At Philly's Trio of Young Arms by Alex Chamberlain
I simply don't have enough good things to say about Aaron Nola. Buy him while you still can.
There was a lot of hype coming into the year on Carlos Martinez. He was an already extremely talented hurler, and it looked like he finally found that elusive third pitch to be able to stick as a starter.
His strikeouts have dried up this year, falling to a career worst 17.9%. The rest of his profile looks the same, but his xFIP is all the way up at 4.30. The key to figuring out Martinez is going to be figuring out what's going on with the strikeouts. Where have all the strikeouts gone?
The first thing I'll point to is his SwStr% and Contact%, which are both career worsts. He's not missing bats anymore. All of those missing whiffs have been on the changeup; it's SwStr% has been cut in half. But the changeup has identical movement and velocity differential to last year. What's going on?
As I suspected, his location is off. Last year he did an excellent job locating it low and away to left-handers (the ideal changeup location). This year he's leaving it up and/or over the middle - hitters aren't going to miss that.
Losing swinging strikes is never a good thing, especially when you're giving back the improvement that was supposedly the key to becoming a star. However, it's very encouraging that his changeup has the same shape and characteristics, so if he can figure out the location of the pitch, he could right the ship. I know you probably wanted a more concrete answer, but I think it comes down to this: if you can get him for a price that bakes in the possibility of his changeup not returning to form, go for it. He has tremendous upside and is seemingly a tweak away. On the other hand, if you can sell him for a price that doesn't acknowledge the possibility that his changeup won't be fixed, by all means pull the trigger because there is risk here.
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