Analyzing Glasnow’s First Stint as a Pirate

Tyler Glasnow has finally pitched himself out of a job for the time being, getting demoted Saturday in favor of Jameson Taillon.

His first extended look in the majors did not go as planned, posting a 7.45 ERA and only going 54.1 innings in his first 12 starts. The strikeout stuff is there (8.28 per nine) and the ground ball rate is promising (43.1%), but just about everything else is somewhere between subpar to disastrous.

Friday was his sixteenth career start, which is roughly a half-season’s worth of starts in an ideal world. The problems he has shown in the majors are no longer skewed by a small sample size. There are clear problems he needs to address, and the Pirates are not going to rush them on his Indianapolis assignment.

As Neal Huntington said during his weekly radio show on 93.7 The Fan Sunday:

“We are not going to put a time frame on Glasnow and be disappointed if he does not come back sooner or be excited if he does come back sooner. Our evaluation will not be based upon time, or a 1.47 ERA or a 4.71 ERA…our evaluation will be based on the things we have asked him to work on.”

So let’s do a little evaluating of our own. Let’s look past the ERA and look at the major league development of Tyler Glasnow: pitcher.


The biggest change in Glasnow’s delivery is him going to a slide step out of the stretch. It’s an effort to try to control the running game, and the drop in stolen base attempts over the year has been noticeable.


Still, batters have a .928 OPS against him with runners on base. Unfortunately, that’s better than the 1.078 mark they have when the bases are empty.

Glasnow’s release point greatly deviated in June, going roughly two-tenths of an inch higher.



Whether this is intentional or not, it certainly was not a good month for him.

But the biggest takeaway I have with Glasnow’s mechanics is his follow through. Glasnow is a tall, tall dude (6’8”). He’s going to have a big stride and a big follow through. The problem is the follow through is a giant step to first base rather than to home plate.


I wrote for The Point of Pittsburgh in May how Felipe Rivero fixed a similar problem and that’s what made him an elite reliever. Either shortening the stride or redirecting his follow through to go straight could yield similar results.


The most obvious differences between this year and last year’s pitch selection are his addition of a two-seamer and increasing his changeup usage. (Brooks misclassifies his two-seamer as a sinker).


I should mention that Statcast had a very different analysis of of Glasnow’s fastball breakdown in June, but they agree he has thrown more two-seamers of late. According to Statcast, 27.27% of his pitches were four-seamers, 41.56% two-seamers.

Glasnow got by being a two-pitch guy in 2016 because he only made a handful of starts and bullpen appearances. He was going to need the changeup, and the two-seamer was going to be his get-over pitch.

Even with those new offerings, the value for each pitch has plummeted. Pitchf/x valued his fastball at -0.1 runs last year, his curve at -0.6 and his change at -0.3. This year, the four-seamer is -11.4, curve -3.5, change -3.2 and the two-seamer at -5.

The reason why is…


Glasnow’s biggest problem his last few years in the minors was control. He would constantly walk three or four per game but get away with it because few could touch his fastball.

He’s actually found the strike zone more lately, not walking a batter in two of his last three starts. But sometimes too much strike zone can be just as dangerous.


That’s a lot of pitches right down the middle, and more than there were last year. And other teams are not missing too often.

Between the change of mechanics and trying perhaps too hard to not walk batters, Glasnow has been serving up meatballs. This might be the toughest problem for him to address in AAA. A mistake there is not going to be hit as hard or as far as it will in Pittsburgh. They can look to see if he’s attacking the four quadrants, throwing the two-seamer down and the four-seamer up like Huntington said they wanted during his show, but he is destined for another baptism through fire at some point.


Glasnow was given a job in the rotation more than he earned one. Eventually, the Pirates reached their breaking point and thought his time in the majors would hurt more than it would help.

There were some encouraging signs this year. He’s throwing his changeup more and is getting a decent amount of whiffs on it. The fastball velocity is up. Walks seem to no longer be crippling him, even if it comes with a whole new batch of worms. Talks of him being a bust or a bullpen arm at this stage of his career are premature.

He has had brief moments of brilliance, but he did not show Trevor Williams’ results or the same level of growth as Chad Kuhl. Demoting him to the minors does not mean he has failed. It probably means there is a blueprint they can work on to make him a major league starter.




2 Replies to “Analyzing Glasnow’s First Stint as a Pirate”

Leave a Reply