Stroman's struggles tied to reliance on sinking pitches

Marcus Stroman is not having the season anyone thought he would. His struggles, as represented by a 5.33 ERA and a weakening strikeout-to-walk ratio, have persisted far beyond the grace period of a slow start. With the Blue Jays promising to push Aaron Sanchez back to the bullpen, there are worries the team could soon have two holes in the rotation to fill.

One can’t help but feel the Jays have taken a perfectly fine rotation and set it on a collision course with failure. Sanchez is a legitimate contender for the role of staff ace, but, by decree of Jays’ management, is destined for the pen despite proving himself more than worthy to keep his role. Meanwhile, Stroman isn’t going anywhere despite rapidly declining results and admitting to the press he’s in full experimentation mode.

Worse, the Jays planned replacement for Sanchez is Drew Hutchison. Though Hutchison’s Triple-A ERA (2.99) is solid, his big-league ERA from last season is an awful 5.57 with a terrifying runs allowed per nine innings mark of 6.17. Hutchison’s 2015 win/loss record of 13-7 only holds water because the Jays offence was wrecking opponent’s pitching every time he was on the mound.

For the record, the Jays had a pitcher at Triple-A Buffalo who was a serious replacement option. Wade Leblanc wasn’t just the best pitcher in Buffalo, he was one of the best in all of Triple-A, sporting a miniscule 1.71 ERA over 90 innings. The Jays traded him to the Seattle Mariners last week for a player to be named or cash.

Leblanc, in case you were wondering, just threw six shutout innings against the St. Louis Cardinals.

There is no use arguing for Sanchez to remain in the rotation, or for Hutchison to remain out. Fans will now have to hope that Hutchison has figured something out during his season in Buffalo, and, more importantly, that Stroman can get his problems sorted out, and fast.

Let’s zero in on a struggling Stroman for a moment.

The 2016 Stroman is a sinking fastball machine. This year, according to Brooksbaseball.net, nearly 55 per cent of his pitches have been of the sinking variety. The trouble is, Stroman’s sinking fastball is good, not great, and his development of it has turned some of his great pitches to merely good.

When Stroman started throwing his sinker last season, hitters hadn’t seen it yet. Scouting reports had him pegged as a four-seam fastball/curve thrower. So, when that sinker popped out as frequently as it did, it baffled a lot of hitters who rely heavily on scouting data and video to prepare for opposing pitchers. Stroman had the upper hand. 

Stroman did feature a sinker before 2015, but it was more of a two-seam fastball that he used to one side of the plate — his right arm side — and was thus only really thrown to one area. It was a compartmentalized pitch that lacked the versatility that his current sinker has.

That doesn’t mean it wasn’t effective. Stroman’s 2014 sinker was thrown 381 times. It was more two-seam (a flatter sinker with a higher horizontal movement score between seven and nine), good for a batting average against of .182 and an ISO of .066. Those are the best results Stroman has ever gotten from his sinker, including 2015, when he came up huge for the Jays in postseason play.

Why was that sinker so good? It wasn’t because he was on top of the ball, or because it went down more, or any of the other things Stroman says short pitchers need to do to have success. It was because it fit his style of pitching at the time.

Stroman threw his old sinker largely inside to righties and away from lefties. Most importantly, he used it as another tool in a pitching repertoire built largely around a hard four-seam fastball. 

Here is Stroman’s sinker heat map for usage in 2014: 

Here is Stroman’s heat map for usage in 2016:

The sinker, now new and improved! Increased versatility and more downward movement! Guaranteed to induce more groundballs! Sounds great doesn’t it? 

Too bad the results stink.

Stroman’s 2016 sinker has netted him a BAA of .305 and an opponent slugging percentage of .445. That’s a far cry from his 2015 season results: 300 sinkers thrown, a BAA of .214, ISO of .095. It’s also a million miles from 2014’s sinker results of a BAA of .182. 

Even so, with previous sinker results like that, it more than justifies scrapping an average four-seam fastball in favour of a sinker, right? 
Wrong. 

The body is not a static device that yields the same results every time. It’s always changing, and as your muscles get accustom to one pitch, release point, grip, etc., it can confuse the others.

In 2015, Stroman’s sinker was a great pitch because it was still strongly influenced by the grip, release point, and style of pitching he used in 2014.

A four-seam fastball requires the pitcher’s fingers to be behind the baseball, cupping all four seams. Stroman’s four-seam fastball has less movement than his sinker — that’s the case for every pitcher’s four-seam fastball — but less movement does not mean less effect. For Stroman, it’s the only pitch he used to pitch up in the zone with, for setup purposes. 

Here is Stroman’s four-seam usage in 2014:

Here is that same usage in 2015:

What these graphs show is Stroman’s migration away from pitching up and in. They also tell us that right handers have more time to get comfortable than they used to, and that all hitters should look down for hard pitches. 

Why? Because Stroman’s overall approach is less about strikeouts and more about ground ball outs by way of his sinker. That’s supported by his precipitously decreasing strikeout-to-walk rate.

Stroman’s transition to the sinker as his new main staple hasn’t just left the four-seam behind as an also-ran pitch, it’s shifted his reliance away from two or three really good weapons to five or six sort of good ones. 

In 2014, Stroman threw 745 four-seam fastballs. His BAA was .264. That’s normal. Remember, his sinker then sported a BAA of .182, while his curve was devastating at .214 and 41 strikeouts. His 2014 slider, cutter and change were all average to poor, but that didn’t matter because he was mainly throwing the three weapons that worked.

Today Stroman’s four-seam fastball yields a BAA .357. He’s only thrown it 44 times, with a handful up in the zone. His sinker nets a BAA of .305 and his curve a .229. His cutter and slider are better, but not in proportion to the losses his other pitches have suffered. 

Today’s Stroman has more tools than his previous incarnation—but he’s getting less work done.

In 2014, when Stroman was throwing predominantly low movement four-seam fastballs, his curve protected them because a curve starts out on the same plane as the four-seam release point and breaks off of it.

Imagine you’re at the plate. You see the four-seam fastball coming in high. Your eyes go up as the four-seam fastball blows past you, up in the zone. The next pitch you see is a curveball. It comes out of the same release point as the fastball you just saw, but at the last moment it breaks down, but about 10 miles per hour slower than that heater. Your mind thinks hard, straight, high, but you get slow, low, and soft. You swing and miss.

Put a little more heat on that curve, take a little off — a guy who throw’s a lot of four-seam fastballs can get great mileage out of a good deuce, which Stroman has. Hitters worry about that combination, so much so that Stroman could, in 2014, sting them with a hard sinker here and there, or mix in a slider if the situation called for it.

A pitcher who relies on horizontal movement via a sinker, on the other hand, absolutely has to have a changeup or a wipeout slider to mask and confuse the trajectory of the sinker. Neither of these secondary pitches are Stroman’s best. 

Stroman’s slider has gotten better. It’s touting a BAA of .231 in 2016 versus a .286 in 2014. The bad news is you only see that slider when Stroman is ahead in the count. Pitchers don’t pitch with sliders all the time like they do fastballs. Stroman’s slider looks more like his sinker, which explains why he’s getting more strikeouts with it now (20) than with his curve (16). Back in 2014, that was 10 to 41, respectively. 

The other bad news is Stroman’s deuce is seeing less play late in counts. What used to be an incredible weapon is now getting used like a “show-me” pitch. It’s an out pitch. Much more so than his slider is and certainly more than his fastballs have become. 

The bottom line here is that in order to make better use of one good pitch, Stroman has made everything else less effective, including his sinker. 

This is no quick fix. Stroman is now caught in the twilight zone of muscle memory. He must either become the sinker/slider pitcher he seems to want to be, or go back and relearn to be a four-seam, power deuce thrower. These are learned behaviours that will take a while to unlearn, or, as pundits like to say, “pitch through.” 

The best thing Stroman can do in the short term is refine his change-up and mix in more elevated four-seam fastballs. He needs to protect what he presently has. The best way to do that is to get hitters off his bottom-of-the-zone-focused arsenal, and have a softer, deceptive weapon that makes his hard stuff more difficult to sit on. 

He’s too easy to hit right now, and as long as he’s relying on his third and fourth best pitches to net outs, I don’t expect that trend to change.