Logan Gilbert: Is There An Answer To His Recent Struggles?

Already in Logan Gilbert’s young career he has seen a 7 start stretch of success, immediately followed by a 7 start stretch of struggles. Obviously, in a player’s first year in the bigs, we expect to see struggles (Kelenic, Raleigh, and Trammell, etc.), but is there anything we can point at to help understand why Logan Gilbert has struggled as of late? Let’s find out.

According to FanGraphs, In a 7 start stretch spanning from 6/6 to 7/18, Logan Gilbert posted a 2.42 ERA in 37 IP. His 11.09 K/9 was above league average, his 2.17 BB/9 was below average, and he was only giving up 0.72 HR/9. Everything was going just as we hoped in a year where consistent starting pitching performance has been invaluable to the Mariners.

The next 7 starts? Not the same story. Gilbert posted an 8.72 ERA in 32 IP. His K/9 decreased to 9.84, and his HR/9 increased up to 2.25 (his BB/9 remained relatively unchanged at 2.25). Point blank, he was striking out fewer batters and giving up more HR. Unfortunately, that isn’t a recipe for success.

There are a few things that popped into my head when trying to justify the recent struggles. Was his fastball velocity down? Was he losing control of his pitches? Were hitters simply figuring out how to hit him now that he’s been in the league for 19 starts?

In Gilbert’s last 3 starts he has posted an abysmal 13.50 ERA and 3.55 HR/9. The last 3 starts have been the worst stretch of his MLB career to this point, and I don’t think that it’s a coincidence that his slider spin rate has been below his yearly average each outing. On August 21st, his worst start in the year in which he gave up 9 ER in 4.2 IP, his slider was 91 RPM below his average according to BaseballSavant.

When Logan Gilbert is at his best, it’s because his slider is effective and compliments his above-average fastball.

Outside of his slider, his arsenal seemed similar to when he was on a hot streak. His fastball velocity and spin rate were consistent, and he wasn’t walking batters at a higher rate than he was before. Considering Gilbert is a fastball/slider heavy pitcher (throwing the fastball 61.5% of the time and the slider 23.9% of the time) if one of his pitches isn’t up to par, it’s not surprising that he’s not finding the same success he was before.

The decreased slider spin rate could also be the reason Gilbert is giving up more home runs. Less spin rate typically results in less movement in offspeed pitchers, and therefore a more “flat” pitch. Since his slider is consistently flatter than it has been, he’s either forced to rely almost exclusively on his fastball or throw that flatter slider that he’s been showing lately. Facing professional hitters, both options above will typically result in more home runs given up.

Gilbert seemed to turn the ship around, tossing 5 scoreless innings against one of the top offenses in the league today vs the Astros. Consistent with what we talked about above, his slider had a spin rate about his yearly average. This combined with one of the liveliest fastballs (+107 RPM above his average and a max velocity of 98.1 MPH) he’s exhibited all year makes for a lethal combo that we know he is capable of showing.