This vaguely reminded me of Dylan Bundy so I looked it up and he did indeed have this treatment before his surgery. I have been wondering if this might be tried for Felix.
Bundy, shut down in Spring Training, received a PRP (platelet-rich plasma) injection to promote healing on April 29 from Wilckens and was prescribed six weeks of rest. He was cleared to begin a throwing program on June 3 but reported feeling discomfort after throwing from 120 feet on June 24.
https://www.milb.com/news/gcs-51848268