MINNEAPOLIS -- The Twins were still waiting to hear from medical experts about the exact nature of Chris Paddack's elbow injury when they placed him on the 15-day injured list on Tuesday, but Paddack is bracing himself for the possibility of a second Tommy John surgery.

All Paddack knew for sure before Tuesday's series opener against the Astros was the official designation of his injury for now: "right elbow inflammation." But he said that after exiting during the third inning of Sunday's 4-3 victory over the A's, his elbow feels "pretty similar" to what he felt when he sprained that ulnar collateral ligament (UCL) last September, ending his season.

There's still no guarantee that there's UCL involvement or that he'll need surgery at all, though it's certainly a possibility. But if imaging reveals that the root cause is, in fact, a torn UCL, Paddack said he would opt for Tommy John.

"Unfortunately, at this point in my career, if it is torn, or anything crazy like that, I think I'm just going to move forward with surgery," Paddack said. "Just because, I would already miss the majority of this season if I did get a stem cell [injection]. ... Let's say it does tear after that -- then I'm looking at not coming back until 2024."

Paddack underwent Tommy John surgery in 2016 while he was a top prospect in the Padres' organization. The injection Paddack mentioned was the platelet-rich plasma injection he received in the elbow last September, which helped him manage the sprain to the UCL without undergoing surgery at the time.

But the right-hander did acknowledge that the injection was more intended to help him manage the UCL impact than heal it altogether. After a six-week shutdown, he was able to have a normal offseason throwing program and Spring Training and made five starts for the Twins this season after he arrived in the Opening Day trade that sent Taylor Rogers and Brent Rooker to San Diego.

Paddack pointed out that he was still up to 95.8 mph in Sunday's start against the A's until that third inning, during which he fired his final fastball at 90.6 mph before mentioning elbow tightness to pitching coach Wes Johnson.

"I think we were managing it," Paddack said. "... The body's crazy, man. A lot of it is mental, unless it is fully torn. You've got to stay positive mentally."

Even though the Twins opened the season with seven starting pitchers on their roster, Paddack's injury does leave them shorthanded, with both Bailey Ober (groin strain) and Dylan Bundy (COVID-19) also currently sidelined. The emergence of Josh Winder, the club's No. 6 prospect, does help -- but depth is currently running thin.

That's the short-term problem. If Paddack's injury does result in a longer-term absence, that means the Twins could have to do without one of their two big-name pitching acquisitions for the foreseeable future. They'll hope it doesn't come to that -- but they're still waiting to see what that future will hold.

"It's crushing from afar to have to see him go through this," said Twins acting manager Jayce Tingler, who managed Paddack in San Diego from 2020-21. "But at the same time, you feel he's been there before, so he's got some experiences to reflect on. ... I was really assured after talking to him, he's in a good place mentally. He's in a good headspace. So now, we're just going to wait and see what the next steps are."