Welcome back to another edition of The Anatomy of An Inning. My name is Jacob Roy, and I pretend to know pitching better than the pitchers themselves. If youre new here or need a reminder of what this is all about, I take an inning from the previous week or so and break it down, one pitch at a time. Each pitch should have a purpose, Im looking at each of them individually to try to go beyond the box score and tell the full story.

Lets go to Sunday, April 14th. The Red Sox bullpen is shorthanded, and they need multiple innings from Justin Slaten to get back in the win column. He enters the seventh inning after getting a quick double play to end the sixth.

Although Slaten is in his first Major League season, its actually his second time seeing OHoppe. The first time, he struck him out on three pitches, including two incredibly ugly swings on sweepers in the dirt. OHoppe is a fairly aggressive hitter, but he does struggle with pitches down in the zone, so Id expect more sweepers from Slaten.

Slaten starts with a cutter on the inside edge for called strike one. Against a righty, youd like to see this down and away, but OHoppe is taking all the way, so well take the free strike. 0-1.

Heres the sweeper he was able to fool OHoppe with twice in their last meeting. This one stays up in the zone, and OHoppe, although out in front, is able to poke it to left field for a lead-off base hit.

Adell is another free-swinger with tons of strikeouts in his game. He whiffs on just about everything, but breaking balls give him extra trouble (47.1% whiff rate in 2023).

Sweeper below the zone for a swing and miss. Given the swing, Id keep throwing it until he proves he can lay off.

Beautifully executed. Do it again.

Here, Slaten tries to elevate with the four-seamer, but misses his spot and leaves it below the zone. Its far enough below the zone that theres no harm done. Id go back to the sweeper.

Theres another sweeper, and Adell lays off. At 2-2, this is an interesting spot. Adell may feel that hes earned a fastball after spitting on the pitch in the dirt. That makes this the perfect spot to throw another sweeper low and away.

Alright, this works. After Adell takes two pitches below the zone, Slaten tries to execute what we saw Kutter Crawford do a few weeks ago. Hes expecting Adell to continue to take any pitch down in the zone as he reads sweeper, so he wants to throw his four-seamer down and away for called strike three. He doesnt hit his spot, but the pitch ties up Adell who grounds out to third for the first out.

Neto is another hitter Slaten has faced this season once already. The first at-bat ended in a strikeout, with every pitch coming in below the zone.

First pitch cutter that misses high for ball one.

Yikes, this could have been bad. Neto stays back on the sweeper that stays inside and pulls it down the line. Fortunately, it goes foul to even the count.

Much better. Slaten goes back to the sweeper, getting it to the glove side, and Neto is out in front this time as he pops it up weakly for the second out, keeping the runner at second base.

Nothing to see here, just know that Slaten once again missed with his fastball and hit Rendon in the shoulder. Still two outs, just get the next guy.

Again, Slaten has seen Rengifo once this season, also striking him out with exclusively off-speed pitches. With the way the defense has played in recent days, a strikeout would be great to end the inning, but any out works.

Heres a 0-0 cutter that misses outside for ball one.

Beautiful back-foot sweeper for strike one. Rengifo is well out in front, tipping his hand hes looking for a fastball. As such, Id do what Slaten did in their last meeting and stick with the breaking balls.

Heres another sweeper that Rengifo fouls off for strike two. Rengifo is more prepared for this one, fouling it straight back. With two strikes, Id go away from the sweeper after Rengifo appeared prepared for it, and instead throw either a cutter up and in, or a high fastball.

Slaten goes back to the sweeper and Rengifo isnt interested. Now, Slaten finds himself in the same position he was in with Jo Adell. Given that Rengifo is a decent fastball hitter and seemed to be looking for a fastball earlier in the count, I wouldnt throw the low fastball looking for a called strike. If Slaten throws something in the top half of the zone, Rengifo will likely read fastball. For that reason, I like the cutter up and inside to jam him and get out of the inning.

Heres the first curveball of the outing, but it only goes about 59 feet and its not enticing to the hitter. With the count full, and Mike Trout on deck, Slaten should throw whatever he feels comfortable throwing for a competitive strike. He hasnt commanded his fastball well this inning; Id expect a sweeper.

And there it is. Its not the best sweeper hes thrown, but it catches the zone in a tough spot and all Rengifo can do is roll over it for the ground ball.

Justin Slaten has been a key piece of the Red Sox bullpen thus far. In this outing, he didnt have great command of his fastball. Fortunately, the sweeper is his best pitch, returning a 40% whiff rate so far this season. As long as hes keeping the sweeper down, he should continue to get whiffs, strike hitters out, and provide lockdown innings in relief.

Read more:
The Anatomy of An Inning: Justin Slaten Has Been One of the Best Relievers in Baseball - Over The Monster