SCOTTSDALE, Ariz. >> Beginning a few bullpen sessions ago, every time Tristan Beck would throw, his right hand would go cold. He would begin to lose feeling. Numbness would eventually set in.

The 27-year-old right-hander brought these symptoms to the Giants’ medical staff, who recommended he visit a specialist. After being scratched from his first scheduled start of the spring Monday, Beck flew back to San Francisco, where vascular specialists at Stanford diagnosed him with an aneurysm in his upper arm, the club announced Thursday.

The outlook for Beck is unclear as he weighs treatment options, which manager Bob Melvin declined to discuss, though he ruled him out for Opening Day and said he would not pitch again for some time. Of more immediate concern was for his well-being than who might backfill his place in the starting rotation.

“We just want to make sure we get it taken care of and he moves on from there,” Melvin said. “It’s obviously not ideal.”

The condition, in which a blood vessel expands or bulges and can eventually rupture, is fairly novel within the game, where tendons, ligaments and soft tissue are usually of more concern. A 40-year veteran of the sport, Melvin said he could not remember the ailment presenting in any other player.

Citing a 1999 study in the American Journal of Medicine that found aneurysms of the axillary artery had been “reported with increased frequency” in baseball players, Dr. Nirav Pandya, an orthopedic surgeon at UCSF, said that while it is “definitely not something that is common,” there is some precedent, particularly in pitchers.

“There are some case reports over the years of pitchers getting aneurysms of their axillary artery where the pec muscles compress the artery,” Pandya said, referencing the major vessel that brings oxygenated blood from the chest to the upper arm.

If treated with surgery, Pandya said, the timetable for recovery is typically about three months. In Beck’s case, he would then need to build back up to a starter’s workload, which typically takes all six weeks of spring training.

“I think we got on it pretty quickly,” Melvin said.

Turning his focus to the field, the Giants’ new manager is now staring down a gaping hole in his rotation, which had already sprung a leak with Keaton Winn’s recurring elbow issues. Beck was slotted in to be their fifth starter, behind Logan Webb, Jordan Hicks, Kyle Harrison and Winn.

Sean Hjelle, Mason Black, Daulton Jefferies and Spencer Howard — arguably the top four potential fill-ins — have yet to record a clean outing among them, with Howard tagged for two homers and Hjelle for three runs on four hits in Wednesday’s exhibition loss to the A’s.

That said, Blake Snell and Jordan Montgomery remain available on the free-agent market.

You don’t have to remind Melvin.

“You think?” he responded when asked if either could help.

Roupp throws live >> One pitcher who isn’t likely to be an option when they break camp but could make his debut later this season is Landen Roupp, a 25-year-old right-hander whom the Giants selected in the 12th round out of UNC-Wilmington in 2021.

After a disc injury in his lower back cut his season short in 2023, Roupp faced live hitters Wednesday for the first time this camp, throwing 25 pitches to non-roster catchers Jakson Reetz, Adrian Sugastey and Andy Thomas while the big-league squad was playing the A’s at Hohokam Stadium.

On the basis of his 1.74 ERA over the 10 starts he made at Double-A Richmond, with 42 strikeouts to just nine walks, Melvin singled out Roupp as one of the pitchers he was most intrigued to see this spring, and he finally got his chance.

“He’s got a really good arm,” Melvin said. “It’s an exciting pitcher.”

Roupp’s signature pitch is his curveball, which Reetz said “starts behind the right-handed hitter,” but what caught the catcher’s attention was his two-seam fastball, which sits in the mid-90s and he called “pretty nasty, as well.” The whole package? “I mean, he’s disgusting,” Reetz said.

Along with top left-handed pitching prospect Carson Whisenhunt, who was shut down last season with an elbow injury, Melvin said that Roupp is one of “the guys we’ll probably slow-play a little bit and see how much time they get in spring, based on injuries last year.

“But guys that could be impactful as the year goes along and might be as talented of guys that we have.”

It remains to be seen whether either will see game action this spring, though Roupp said he’s “hoping and praying” the coaching and medical staffs will allow for it.

There is no timetable for Whisenhunt to face live hitters, Melvin said, a necessary step before stepping onto the mound in a game.

Roupp, who ended 2022 with five starts at Double-A in addition to the 10 he made last season, said he hopes to begin the season at Triple-A Sacramento.

“I would love to start in Triple-A, but if I’m healthy and pitching I don’t care,” he said. “I’ll pitch wherever, honestly, but Triple-A is definitely the goal.”