Right-hander Kohei Arihara has an aneurysm in his right shoulder and will undergo surgery, general manager Chris Young said prior to Saturday’s game against the Astros at Globe Life Field. The procedure will be to repair a posterior circumflex humeral artery aneurysm, and it will be performed by Dr. Gregory Pearl in Dallas on Thursday.

The estimated timeline for recovery is at least 12 weeks. It is unclear whether Arihara will pitch again this season.

Arihara had already been on the 10-day injured list for what the Rangers termed a contusion on his right middle finger. The discomfort Arihara was feeling in the finger was apparently connected to the aneurysm; after throwing a bullpen session last Monday, the right-hander continued to feel discomfort, leading to the diagnosis.

The Rangers signed Arihara last December out of Japan, where he pitched in the Nippon Professional Baseball organization for the Nippon Ham Fighters from 2015-20. In seven starts for Texas this season, he has a 6.59 ERA.

Prior to his last three outings, Arihara had a 2.21 ERA on the season -- but since April 25, his ERA is 17.28. Young said the aneurysm likely played a role in Arihara’s struggles of late.

“It’s obviously a disappointing outcome for both Kohei and the Rangers,” Young said. “But we certainly wish him the best and are very confident in the medical treatment he has received. … It’s a very serious condition if it’s not treated, and we’re very fortunate that this was caught early and we didn’t continue to push it with him.”

Young said the aneurysm procedure is “one aspect of thoracic outlet syndrome surgery,” but specific to the blood clot in the shoulder as opposed to a full TOS procedure.

As for what the Rangers will do to fill Arihara's spot in the rotation, Young said those decisions are yet to be made.

"I don't want to comment yet until I sit down with [manager Chris Woodward and president of baseball operations Jon Daniels], and we'll kind of walk through the next steps and plan out the next few weeks," Young said. "We do have some off-days coming up, so it gives us the flexibility to juggle the rotation a little bit."

Reliever Hunter Wood, who came into Saturday’s game in the seventh inning, exited after getting the first two outs due to right elbow tightness. The right-hander walked Bregman and threw a wild pitch that enabled Bregman to advance to second base before coming out of the game. Wood will be reevaluated Sunday.