Why the Arizona Diamondbacks optioned outfielder Alek Thomas to Triple-A Reno

OAKLAND, Calif. — Given that the Diamondbacks bullpen threw a combined 137 pitches Tuesday night, a move to add a new reliever before Wednesday’s game was inevitable. It’s the corresponding move, though, that holds more significance.

In order to clear a roster spot for Luis Frías, the Diamondbacks optioned centerfielder Alek Thomas to Triple-A. Given the discourse around the team during spring training, it provides a stark reality, even amid an excellent 24-19 start. Much of the Diamondbacks’ preseason optimism centered around their young, fast, exciting starting outfield. Now, two of those starters — Thomas and Jake McCarthy — are working through struggles in Reno.

Thomas got more of a leash than McCarthy, who was optioned on April 25. The first sign that could be changing came during the Diamondbacks’ most recent homestand, when Thomas was moved into a platoon role that would involve him only starting against right-handed pitchers. Ultimately, though, that wasn’t a role that the team wanted him to fill long-term.

“We feel like he's just too talented for that,” Manager Torey Lovullo said before Wednesday's game against the Athletics. “Mostly because of what he does defensively. He's just too good of a player. And he should, with his hand-eye coordination, be an everyday player without giving any consideration as to who's pitching.”

This year, Thomas is hitting .195/.252/.327. He is just 1 for 36 with one walk and 14 strikeouts against left-handed pitchers.

In order to fulfill the promise that he carried as a top prospect, when he was considered a potential star, the Diamondbacks felt that Thomas needed to rework some things mechanically. He has a unique swing that pulls him off the plate towards first base, often leading to groundballs rolled over to the right side of the infield. Thomas also acknowledged recently that he struggles to identify strikes on the outer half of the plate against lefties.

“There's a lot of excessive movement with the lower half which is creating some force moving forward, I know to impact the baseball but I feel like it was changing his sightlines,” Lovullo said. “So we want him to slow some things down. And I think it's a lower half issue more than anything. So specifically, maybe getting grounded, spreading out a little bit. Not totally eliminating the leg kick but controlling the leg kick a little bit and specifically doing better left on left.”

The Diamondbacks have not been blind to the problems created by Thomas’ unique swing, but they’ve tried to address it with minor alterations here and there. Now, they’re taking a more comprehensive approach.

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“We felt like over time that he was gonna need to make some sort of an adjustment,” Lovullo said. “While we needed the pitching and we're gonna send him down, we felt like this was a good opportunity for taking advantage of that.”

While Lovullo said that Thomas’ defense made it hard to take him out of the lineup, his advanced numbers on that side of the ball have not been as good as they were a year ago. Last year, he was worth seven outs above average, per Statcast, making him a 92nd percentile defender. This year, his defense ranks in just the 45th percentile.

Lovullo said those struggles did not make it any easier to remove Thomas from centerfield on a daily basis. It is, however, something the coaching staff has been aware of. With Thomas scuffling at the plate, the staff didn’t want to overload him with too many things to work on, leading the focus to primarily be on his at-bats. Going to Triple-A will give him an opportunity to dial in on the defensive side as well.

“There were some things he needed to work on,” Lovullo said. “Some routes specifically. Closing on the ball at the right angle. And he'll be fine. I think there's just some tweaks he can do out there and it'll take care of itself quickly.”

This article originally appeared on Arizona Republic: Reasons why Arizona Diamondbacks optioned Thomas to Triple-A Reno