That's precisely what happened to Padres pitcher Blaine Boyer, a non-roster invitee who is trying to win a job on the 25-man roster.
Boyer had labrum and rotator cuff surgery in 2006 while a member of the Braves. When he got back to the big leagues the following season, he discovered that his best pitch -- his curveball -- wasn't working for him.
"That was my go-to pitch," Boyer said. "When I came back in '07, I had to remake myself a little. You're out there trying to survive and get guys out."
It worked, to some degree, Boyer said.
Boyer spent parts of the three seasons with the Braves before being traded to the Cardinals in 2009. He bounced around baseball after that and didn't play at all in 2012, before getting back into pro baseball last season, first with the Royals' Triple-A affiliate and later in Japan.
Boyer, 32, has never felt better. And, better still, his curveball has returned.
"I honestly feel like my stuff is better than it's ever been," Boyer said. "It sort of makes sense now. After my surgery, I had a hard time getting on top of the ball. Now, I can do that."