Here's what the doctor in the Baltimore Sun article said:
Gilotra, who is not treating the Orioles’ closer, said the UCL is unneeded in most aspects of daily life, with athletic acts such as hard throwing, gymnastic landings and powerlifting being the ligament’s primary applications. Bautista, who has yet to address the injury himself, could still perform light throwing even if his UCL wasn’t intact, Gilotra said, though it wouldn’t necessarily make much sense for him to do so.
“If it’s fully torn, he could still do it. But if it’s fully torn, why would you?” Gilotra said. “Like, what are you warming up for next, right? … Usually, you wouldn’t do that if you were preparing for a reconstruction or even a repair.
“If you’re just playing gentle catch, you’re not hurting yourself. But for the high-level athlete, there’s no reason just to stay warm, so I honestly don’t know what that means. Does that mean that he, in secret, had some of these [PRP] injections already and he’s just slowly returning to throw? I feel like that’s unlikely that it would be such a secret, but it is strange. … I think the confusing part then is what’s next, right? Is this in preparation for harder throwing later?”