Aaron Sanchez Is A House Of Cards

Regression is coming if Sanchez can't fix some worrying trends.

aaron-sanchez-blue-jays-2018
Photo: Keith Allison/Flickr

Aaron Sanchez has produced some good numbers this season. His ERA sits just under four, with a batting average against of .257, and a rate of about one home run allowed every nine innings. His strikeout rate is the highest it’s been since 2016 when he grabbed the American League ERA title. Unfortunately this is where the good news ends.

There is an avalanche of other statistics suggesting that Sanchez has been the beneficiary of good luck. Curiously, he has fared alright against left-handed hitters this year. It’s righties who have given him the most trouble. Let’s look at where his numbers stack up:

Aaron Sanchez vs RHH in 2019
Min. 75 PA vs RHH for xwOBA. Min. 20 IP vs RHH for other stats. Through June 5th, 2019
K% - BB%FIPxFIPERAxwOBA
Sanchez4.4%5.375.703.86.371
MLB Average15.1%4.344.314.39.320
Percentile Rank2nd19th4th52nd14th

The ERA is the only thing above average. Actually, it’s the only thing that’s not terrible.

ERA predictors, such as xFIP and K% minus BB%, have Sanchez sitting almost dead last when he faces same handed-hitters. It’s a group that includes Mike Fiers (5.45 ERA), Drew Smyly (7.15 ERA), and Dan Straily (10.64 ERA), who have not been as lucky against righties.

In his breakout 2016 season, Sanchez held righties to a .231/.273/.318 triple slash line and a 2.81 FIP. This year it’s .289/.406/.430 and there are a few reasons why it’s been so much worse.

Fastball Velocity

He’s lost a full tick on both the four-seamer and sinker since 2016. The average four-seamer has dropped from 95.6 mph to 94.7 mph in 2019. Its effectiveness has dropped in kind.

For his career, four-seamers thrown between 94-95 mph produce a .402 wOBA against. Between 95-96 mph it drops to .362 wOBA.

The sinker follows a similar pattern, and this is what you’d expect. Higher fastball velocity is better for a pitcher, all else being equal.

Fastball Location

The fastball command Sanchez showed in 2016 has unfortunately shown no signs of returning.

Compare this heat map from 2016 on four-seamers against right-handed hitters to the one from 2018-19.

aaron sanchez four seamer RHH 2016

The cluster in 2016 is much tighter. He attacked right-handed hitters up and away pretty consistently. Since 2018, he’s not reaching the top of the strike zone with the same consistency and instead catching too much of the middle of the plate. And when his four-seamer is located lower, it’s not changing the eye level of the hitter as much when he pairs it with the curveball.

Let’s look at his sinker from 2016, and again compare it to 2018-19.

aaron sanchez sinker RHH 2016 aaron sanchez sinker RHH 2018-19

It’s a testament to how much Sanchez’s sinker moves that throwing it in the heart of the zone actually worked in ’16. But it did. The glob over the past two seasons shows something else entirely. It’s a mess. It ends up out of the zone more often, and in all directions.

The results have been predictably poor. The sinker to right-handed hitters in 2016 produced a .269 wOBA. In 2018-19 it’s risen to .372. At least he’s following the league-wide trend of throwing fewer two-seamers (65% in 2016 down to 41% in 2019). The problem is that his four-seamer isn’t getting the job done in its place.

Trouble From The Stretch

His already-spotty command gets worse with men on base.

Empty, he’s posted a 9.3 K/9 and 4.0 BB/9, good enough for a 3.57 FIP. With runners on, those rates converge to 6.2 K/9 and 5.9 BB/9, and his home run rate nearly triples. He’s throwing a few more fastballs but not to the extent that we can blame it on a changing pitch mix.

He doesn’t produce enough swings and misses, or limit walks, to get away with struggles from the stretch. It’s something he’ll have to correct.

Overall, not much has changed from last season when he posted a 4.89 ERA. He’s still battling finger injuries, having a lot of trouble second and third times through the order (a 6.46 and 5.02 ERA respectively), and is walking way too many batters.

The blisters and nail problems have certainly contributed to his ineffectiveness. The root of all his struggles may simply boil down to that. Would moving him to the bullpen be the fix? Perhaps. But that seems like it should be the last resort.

It seems too simple to just point to fastball command and finger issues as the root of his struggles the past three partial seasons. But I don’t see a bigger red flag than that. He’s got a true weapon in the curveball and, to his credit, he’s throwing it more now than ever before. The sinker isn’t getting him as many ground balls as it used to, but that’s ok because his changeup is making up for it. And, you guessed it, he’s throwing more changeups the past two seasons.

But none of this is going to work if he can’t locate fastballs. His ERA is a mirage and both he and the medical staff must feel some pressure to figure this finger business out. Because until then, Sanchez isn’t going to be effective. And he won’t be worth much as trade bait either.