AL Starting Pitcher Z-Contact% Improvers

What do we do to analyze players this early in the season? Focus on the underlying metrics that stabilize quickest and try to spot early changes. While our sample size stabilization points don’t include any advanced metrics, I would bet that the plate discipline metrics, including Z-Contact%, would sit on the low end in terms of how many plate appearances or batters faced they require to reach the calculated stabilization points. So let’s dive into the American League starting pitchers that have improved their Z-Contact% most from last year. Is there anything more illustrative of the quality of a pitcher’s stuff than making a batter miss a pitch in the strike zone?

Wowzers, Jason Vargas! The comparison to last year is kinda silly, considering he threw just 12 innings, facing 47 batters. However, last season was his lowest Z-Contact% to begin with, so this improvement is even larger if looking at his historical rates. How has the 34-year old suddenly become a strikeout machine?! He’s not suddenly throwing any harder and his pitch mix has remained the same. His changeup has always been fantastic, though this year its SwStk% is all the way up at an absurd 30.8%. The big driver is that his four-seamer is suddenly inducing whiffs, when it’s been ohhhh so bad in the past.

My initial inclination would be to guess that he’s now throwing the pitch higher in the zone. High fastballs generate more whiffs than low fastballs. That was indeed the case during his short time last year. But, not so this season so far. In fact, his vertical location is the lowest in the zone it’s ever been! So without an explanation I could dig up, this looks like a complete fluke, as there’s no reason his changeup should also improve from top notch to historically good.

So much for Chris Sale’s strikeout rate dip last year. This improvement looks better because of last season’s highest Z-Contact% since 2012, so it appears he’s back to normal. And hey, his velocity has rebounded too! He’ll battle for second best fantasy pitcher honors once again.

While I’d like to see the ground balls return to James Paxton’s profile, I don’t think anyone could complain. His fastball velocity hasn’t quite been maintained from last year, but it’s still above his pre-2016 days. Getting back to his ground ball rate, his fastball is generating a low-teen SwStk%, nearly double his mark last year. It’s time yet again to investigate the vertical location of the pitch. Unfortunately, no dice once again. He’s throwing it a bit higher than last year, but it’s still low in the zone. I highly doubt he could maintain his fastball SwStk%, but his secondary pitches remain super strong, so he should stick in the low-to-mid-20% strikeout rate range.

Ian Kennedy has essentially maintained his career best velocity from last year, but now his changeup has been even more insane than Vargas’. What’s going on in Kansas City?! Are naked girls being unleashed in the outfield every time a Royals pitcher throw a changeup, thereby distracted the batter from making contact?

Matt Andriese is one of the few pitchers on the list whose Z-Contact% has significantly improved, yet his strikeout rate has barely budged. His scouting grades are meh, he was never an exciting prospect, and his minor league numbers were mediocre. But with a good defense behind him and a friendly home park, he’s a respectable stash in even shallow mixed leagues.

Tyler Skaggs hasn’t maintained his increased velocity from last year after returning from Tommy John surgery, but it’s still well above his pre-2014 days and all three of his pitches have generated a SwStk% in the double digits. There are some red flags here such as a fly ball rate that has jumped above 40%, but with an ERA over 5.00 and a sub-4.00 SIERA, he should post much better results the rest of the way.

Seriously, who has taken over James Shields‘ body? I can’t for the life of me recognize who this masked man is anymore from his statistical profile. A career best Z-Contact%, career worst F-Strike% and walk rate, a hilariously high 58.1% (!!!!!) fly ball rate, and his signature changeup being thrown only about 10% of the time, half the frequency of last year? Good luck trying to project his performance moving forward, but there’s little here that’s inspiring.

The pitch to contact CC Sabathia has officially arrived! Now sporting just a 14.9% strikeout rate! Odd, he’s inducing whiffs like normal and has posted the second lowest Z-Contact% of his entire career. So where the heck are the strikeouts?! His xK% is better at 17.4%, so this looks like some bad sequencing early on.

Marco Estrada is inducing whiffs more than ever before, so as a reward, his strikeout rate has…declined. Oddly, he hasn’t induced a popup yet, as he’s typically been a master of, but has offset the lack of easy outs with a crazy low line drive rate.

We all figured that Rick Porcello would disappoint compared to his Cy Young campaign last year, but probably didn’t envision a 7.00+ ERA after his first three starts. Guess what? His skills are just as good, if not better, than last year. The Z-Contact% sits at a career best, which has boosted his SwStk% above 10% for the first time, all on the heels of an amazing slider. That pitch has always induced below average whiffs for the pitch type, so I’m not sure what he’s doing differently whether the pitch has improved or it’s a small sample fluke. Whatever the answer, his .385 BABIP and 20.8% HR/FB are sure to plummet toward the league average, so don’t panic Porcello owners.