Guerrier, on the disabled list, underwent a platelet-rich plasma injection Thursday and will have another next week and possibly another a week later. In the meantime, he will not throw a ball.
Trainer Sue Falsone said Guerrier has scarring in the tendon from repeated traumas and they've been unable to put down the inflammation it causes. If this approach doesn't work, surgery is "the last option," she said.
Guerrier, disabled since April 19, had a similar injection three weeks ago, but resumed throwing after several days and has experienced discomfort that heightened during a bullpen session Wednesday, after which the decision was made to try a new course of action.
"Now I'm shut down completely, and we didn't do that last time," Guerrier said. "I'll have two injections and how I feel will determine if I have a third and I'll start throwing after that, but I'll have zero pain when I come back. I was trying to convince myself I could do it the other way."