DENVER – Luke Weaver underwent an MRI on Monday and was diagnosed with a “right forearm strain,” Diamondbacks manager Torey Lovullo said, a prognosis he seemed to frame as good news for the team’s talented young right-hander.

“We are very hopeful in feeling that it won’t require a procedure,” Lovullo said. “That’s where I’m at right now with the information I’m gathering.”

Still, Weaver is planning to seek a second opinion on the MRI results. Lovullo said team physician Dr. Gary Waslewski offered the initial opinion.

Weaver exited his start on Sunday in San Francisco with what the team had called right forearm tightness. After throwing a pitch in the sixth inning to the Giants’ Buster Posey, Weaver was seen stiffening his arm and flexing his fingers.

Weaver was placed on the 10-day injured list on Monday, meaning he is certain to miss at least two starts. Even if Weaver doesn’t need surgery, it could still mean a prolonged absence for him, which would be an unwelcome development for the Diamondbacks. He had been in the midst of a breakout season, posting a 3.03 ERA through 11 starts.

Earlier in the day, Lovullo said he was trying to remain optimistic yet realistic, particularly after what he and the club experienced last year with right-hander Taijuan Walker.

After leaving a start at Dodger Stadium with forearm tightness in April 2018, Walker said he “felt strong” and passed all the physical exams administered by the club’s training staff.

However, an MRI revealed a torn ulnar collateral ligament; Walker underwent Tommy John surgery shortly after.

“We just felt like it was going to be some muscle fatigue or tightness that all pitchers go through,” Lovullo said. “That’s what I really believed until the moment I got those results. …

“I’m going to remain optimistic; I live in the clouds where the rainbows and butterflies fly every single day. But I’m going to be a little more open-minded after what I walked through with Taijuan last year with my own personal thoughts.”

Lovullo said the club hasn’t determined what it will do with the rotation spot; Triple-A Reno right-hander Jon Duplantier is the most logical candidate.

“Losing him is going to impact us, there’s no doubt about it,” Lovullo said. “I want to be realistic about it.

“But another part of that reality is we have some really good young pitchers in the system and other candidates that can get outs and have proven themselves here. We’re lucky that we have that depth. It’ll be a time for them to step up.”

Lovullo said right-hander Taylor Clarke will remain in the rotation and pitch on Thursday, as expected. If Duplantier is the choice to replace Weaver, the Diamondbacks would have three rookies in their rotation, though right-hander Merrill Kelly isn’t as young or inexperienced as the other two.

But Lovullo said he views both Clarke and Duplantier as mature beyond their years. Neither is as old as the 30-year-old Kelly, but both Clarke (26) and Duplantier (24) are a bit older than the typical top prospect.

“I’ve mentioned the mound presence with both guys; that’s really important,” Lovullo said. “Even though Taylor Clarke has only had (three) outings up here, he doesn’t pitch like that. He pitches like he’s been here for five years.”

Short hop

Right-hander Jimmie Sherfy was recalled from Triple-A Reno to take Weaver’s place on the roster. Sherfy had been sent down just last week, but because he was replacing an injured player he did not have to remain in the minors the requisite 10 days. He worked 1 1/3 innings, throwing 42 pitches, in relief on Monday afternoon.