April 25, 2016

Jake Arrieta – Truly in a “league of his own”?

Jake Arrieta is a very good pitcher having an incredible run at the moment, but is he – as ESPN suggested – in a “league of his own” at the moment? Is he, as Bleacher Report and NBCSports claim, the best pitcher in baseball? Has his current run surpassed the rest of the MLB field? In the case of at least one of his peers, the answer is “no.”

Jake Arrieta does pushupsHe’s also very good at making you feel bad for skipping your workout days

Jake Arrieta is very, very good at this whole “baseball” thing. We want to start out making that very clear. At no point is this article even remotely a suggestion that he’s not a great player who is pitching at an insanely high level.

However, what we will argue is that not only is he not “in a league of his own” above the rest of the MLB pitching ranks, he’s not even alone atop those ranks.

Much has been made of Arrieta’s current run of success. As the ESPN Stats article points out, since his last loss (which came at the hands – arm? – of Cole Hamels and his no-hitter), Arrieta has put up an insane stat line: 17 starts, 15 wins, 0 losses, and a microscopic ERA of 0.65. Throw two no-hitters in the mix and it’s even more incredible.

DSCN0048 Jake ArrietaThat’s a bat guano crazy stat line and we won’t say it isn’t.

Bill Baer at NBCSports says Arrieta is the best pitcher in baseball. Jacob Shafer at Bleacher Report agrees. Jayson Stark follows ESPN Stats in saying Arrieta’s numbers “are out of this world”, and as long as we only look at wins and ERA (which are the heavy focus of those articles), then Arrieta is indeed without peer.

However, if we looks at on-field outcomes other than just ERA, then he’s got company in his performance over his past 17 starts. Here’s a comparison between Arrieta and a fellow National League ace:

Jake Arrieta & Clayton Kershaw over their past 17 starts

While the ERA is obviously higher (a “gigantic” 1.54), player A has pitched better than Arrieta in most other aspects of the game. He has struck out more batters, walked fewer, given up less contact, and gotten more swinging strikes. Those are sort of the basics of effective pitching, and player A is a decent amount better at all of them.

Clayton Kershaw on July 23, 2015 (1)Player A is obviously Clayton Kershaw of the Los Angeles Dodgers (if you guessed that, you get nothing, it wasn’t that hard…showoff). However, we’re evidently all getting bored enough of Kershaw’s dominance that we’re not content to say “Arrieta’s pitching amazingly” but go further to say “And he’s alone in his greatness”, which just isn’t true.

Here are the two pitchers over the past calendar year:

Jake Arrieta & Clayton Kershaw over the past calendar year

Again, Kershaw’s struck out more, walked fewer, given up less contact, and gotten more swings and misses. Their ERAs are also much closer in the larger sample size.

Expanding the comparison one step further, the ESPN article makes mention of Arrieta’s last truly bad game, back in April of 2013 (back when he was with the Orioles) and how he’s “taken off” since then.

After that outing (three years ago to the day from his no hitter), he was sent down to the minors, jumped back up for a single start, and then was traded to the Chicago cubs. He spent a bit of time at AAA Iowa, and then returned to the Cubs a completely different pitcher. Evidently Arrieta really likes deep dish, because here’s his past three years compared to his career to that point:

Jake Arrieta before and after Cubs

Amazing difference. And just to rain on the parade once more, here’s Kershaw since the point of his June, 2013 recall to the Orioles:

Jake Arrieta and Clayton Kershaw over the past three calendar years

Now, no one is claiming that Arrieta’s been better than Kershaw over the past three years, but it’s meaningful to recognize that the 30-year old Arrieta’s recent run (read: smallish sample) is way ahead of his career performance, whereas no matter which slice we take from Kershaw reveals pretty much consistent performance for 3+ seasons.

Not Open-and-Shut in favor of Kershaw

This isn’t to say that Kershaw’s better at everything. Yes, Arrieta’s crazy-low ERA has been driven by a crazy-low BABIP (.191, 50 points lower than his mark over the past three years), but it’s not as abberant as you might think.

As Dave Cameron over at FanGraphs notes, Arrieta is one of the best pitchers in baseball at inducing weak contact. The only pitcher who’s done it better over the past couple of seasons is Dallas Keuchel. He’s also very good at inducing ground balls.

Combine weak contact with few fly balls, and Arrieta ends up with a very low “normal” BABIP and a very low HR/9 rate. Since the beginning of 2014, MLB average Soft% has been 18.5% and Hard% has been 29.0%; Here’s Arrieta and Kershaw over their past 17 starts:

Jake Arrieta & Clayton Kershaw over their past 17 starts

Both are better than average, but Arrieta has induced more than 50% more softly hit balls and given up 25% fewer hard hit balls than Kershaw. Couple that with a flyball rate about 60% of Kershaw’s, and we get an absolutely nuts 0.22 HR/9. This profile isn’t just over Arrieta’s amazing stretch, it’s born out in bigger samples as well – here are the stats for the past calendar year:

Jake Arrieta & Clayton Kershaw over the past calendar year

Arrieta’s still well ahead of Kershaw in those stats – though not by nearly as much (and the related stats are consequently much close as well). Over the past three years, the soft/hard hit rates are still in Arrieta’s favor, though again, the gaps close just a bit more:

Jake Arrieta & Clayton Kershaw over the past three calendar years

Whatever magic transformation Jake Arrieta underwent upon heading to the Cubs has only increased in potency as time has gone on (our bet’s still on the deep dish). So, is the question “will Arrieta come back down to earth?”

Probably not the Next Koufax

Well, yes, it’s almost certain he will because that’s what usually happens to people who perform at a level well above a significant sample of previous performance (almost certain though, not absolutely – if we’d applied the same analysis to Sandy Koufax’s “transformation” after his 6th year in the league, we’d have been dead wrong).

1962 Bell Brand Sandy KoufaxAssuming Arrieta isn’t the next Koufax (though how cool would it be if he was?), the question is how far will he regress as he returns to “normal.” Well, if all he does in the near future is perform at his 3-year average rate, then he’ll still be great.

His 3-year FIP of 2.66 would have tied for 3rd best in the MLB this past season (though maybe it should be 2nd, because Arrieta’s actual 2015 was 2nd at 2.33). His xFIP of 2.89 would have been 7th. His ERA of 2.25 would have been 4th (again, one of the people “ahead of him” was his actual 2015).

His K-BB% of 19.1% would have been 13th (or 12th), his soft hit rate would have been 6th (5th), his hard hit rate 3rd (2nd), and his HR/9 would have been 5th (4th).

Jake Arrieta is in a League of Two

It’s that last paragraph that captures Arrieta’s true greatness, and it’s easy to miss at first blush. At the end of Cameron’s article is the single sentence: “that he also runs excellent strikeout rates and doesn’t walk anyone makes Arrieta an unquestioned ace,” and it’s worth examining that combination more closely.

If we look at the beginning of 2014 to today, his nearly unique combination of skills really stands out: In those 2+ seasons, Arrieta is 3rd in soft hit rate and 2nd in hard hit rate. The only player ahead of him in both is Dallas Keuchel (2nd and 1st, respectively).

Dallas Keuchel on August 25, 2015

He’s also one of the few MLB players to out-beard Arrieta

However, whereas Keuchel is 30th in MLB in K-BB% (15.0%), Jake Arrieta is 9th (21.0%). Only one other player is in the top-10 in all three stats (say it with me now): Clayton Kershaw.

Since the beginning of 2014, Kershaw is 1st in K-BB% and 9th in both Soft% and Hard%. Only two other pitchers are even top-20 in all three: Zack Greinke (13/13/18) and Chris Sale (2/18/16).

Looking at those four names, it’s almost as if the combination of striking out a lot of hitters, walking few, and inducing weak contact makes a pitcher absolutely nasty (it does, it totally does).

Has Jake Arrieta been “in a league of his own”? Absolutely not. Is he the best pitcher in MLB right now? We’d argue not, though we’ll certainly listen to arguments otherwise. However, the only reason he’s not is because Kershaw is – and has consistently been for 3+ seasons – performing at near-Pedro/Koufax levels.

If the only reason you’re not the best is because someone else is putting up an even more historically excellent performance, then there’s absolutely no shame in being a close second.

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