This player recovered properly.
He had elbow surgery. A player does not bounce back 100% in less than a year after elbow surgery.
He had two injury recovery cycles at the end of the previous season. Not much recovery there because it was just after surgery. During the offseason, he did bounce back a bit in some of the raw ratings (health, durability, stamina, arm strengh, Velocity). He will only recover the skill ratings (effectiveness, control, pitch grades, etc.) with time on the mound during the season.