Why Luis Morales’ New Sinker Matters More Than His Spring ERA

If everyone stays on turn, Luis Morales will have one more start to make this spring, facing the Chicago White Sox in the final game of camp. From there, the A's will have three days off before the regular season begins on Friday, March 27 in Toronto.

So far this spring, Morales has struggled. The 23-year-old righty out of Cuba looks to be a member of the A's rotation, either in the fourth or fifth spot, but his production to this point hasn't been terribly inspiring if you're just scouting the stat lines.

He's posted a 7.16 ERA across five appearances (four starts) and 16 1/3 innings of work. In that span, he's given up 20 hits, walked ten and struck out 15. Opponents are batting .299 against him and he's posted a 1.84 WHIP—neither of which are good signs.

But as we mentioned recently, Morales has been hard at work on a new pitch this spring, and that could very well be the reason that he hasn't been matching his production from his rookie season in Sacramento.

Diving in on Luis Morales' new sinker

In yesterday's start against the Chicago White Sox, Morales lasted 4 1/3 innings, gave up four hits and three walks which led to five earned runs coming across the plate. He was also tagged for a couple of home runs and struck out five.

Here is how that pitch distribution panned out.

Pitch	Usage 3/17	Usage '25	RHH %	LHH%	Whiffs
4-Seam	39%	52%	29%	54%	3/13 (23%)
Sinker	30%	--	47%	5%	0/9 (0%)
Sweeper	21%	27%	18%	24%	7/19 (37%)
Changeup	5%	13%	0%	14%	3/5 (60%)
Slider	4%	8%	5%	3%	1/4 (25%)

This table gives you an idea of what pitches he's been focusing on this spring and what he was working with last year, in addition to how he was attacking hitters with it on Tuesday. The sinker was his main fastball against right-handers, while he barely used it against lefties.

There's one more piece of data could be helpful with those whiff rates from yesterday, and that is what his arsenal was providing last season. The four-seamer had a whiff rate of 15.3%, while the sweeper (38%), changeup (25%) and slider (38.7%) were all more effective offerings at getting swings and misses.

As for how the sinker performed when the White Sox made contact, here are all of the batted-ball results.

Second inning — Austin Hays groundout, 100 mph exit velocity. Luisangel Acuña called strike three.

Third inning — Derek Hill groundout, 72.4 mph exit velo. Chase Meidroth home run, 99 mph exit velo. Austin Hays double, 98.7 mph exit velo.

Fourth inning — Chase Meidroth flyout, 79.8 mph exit velocity. Miguel Vargas called strike three on a 98.3 mph sinker to end the inning.

For the Meidroth home run, it came on the fifth sinker of the at-bat. Two had been called balls, one was a called strike, and one was fouled off. The fifth was parked over the fence.

The White Sox scored five runs in the bottom of the third inning, and Morales was even lifted after some struggles before re-joining the party in the fourth. He wasn't able to locate the sinker very well for a swath of pitches in the third, which led to some of the struggles he displayed. While the sinker wasn't the sole reason for the White Sox outburst, it wasn't always helpful, either.

In his previous start on March 11 against the Arizona Diamondbacks, he was again focusing the sinker on right-handers, though he threw fewer of them thanks to Arizona's left-handed heavy lineup that day. He only received four whiffs on 75 total pitches, and all four came on the sweeper.

Why this matters

While the sinker isn't exactly a perfect pitch just yet, it does give him another look against right-handers, while also becoming a bit of a ground-ball getter for him. Last season he had just a 35% ground ball rate, which was well below the league average of 41.8%. We saw some fly ball pitchers struggle in Sacramento, and hopefully this helps him to avoid that fate.

So we know that he's been working on a new pitch, and that there's still a bit of a learning curve with it. But we also know that he's had some success with his other offerings in the big leagues, as well as at different points this spring. This season could just be about finding the right pitch mix for him to get that sinker mixed in there, while letting his other offerings go out and carve up opposing offenses.

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