PHOENIX (AP) — Sean Doolittle had a cast covering his right wrist three years ago, the latest in a series of injuries that cost him nearly three years of his professional career.

With his dreams of reaching the major leagues as a first baseman slowly fading, Doolittle made sure he wasn’t going to spend the rest of his life wondering if he could have reached the big time: he returned to his roots as a pitcher.

“When you look back and see where he’s come from, it’s pretty amazing,” Oakland Athletics manager Bob Melvin said Sunday. “From when I first saw him, I was surprised. The next thing you know he’s closing a game against the Yankees.”

Doolittle began the transition during the summer of 2011 at extended spring training in Phoenix. With the cast making it impossible to put on a glove, he needed someone to catch for him as he began a long process of building his strength and stamina.

“I was on a six-week long toss program before I even got on a mound,” Doolittle said. “I’m grateful for the way they brought me along.”

He no longer has to worry about his place with the Athletics, though he continues to work at his craft. He’s a valued member of their bullpen and part of the reason the A’s will start the season as two-time defending AL West Division champions.

Doolittle credits several people who helped him make the transition, including his brother Ryan Doolittle, A’s director of minor leagues Keith Lippman and A’s pitching instructor Garvin Alston. But he said it started with Virginia pitching coach Karl Kuhn.

“I did not pitch at all since college,” Doolittle said. “When I got back on the mound so much of it came back so fast because he drilled it in.”

Doolittle drew attention as a pitcher and offensive player out of Shawnee High in New Jersey, and there were teams that liked him as a pitcher with Virginia. The A’s originally drafted him as a hitter in the 2007 amateur draft, making him the 41st overall pick.

“I didn’t have a preference,” Doolittle said. “I wanted to be good at both.”

He was a top prospect his first 2 1/2 years in the organization. Injuries began robbing Doolittle of time. He underwent a pair of knee operation sbefore seriously injuring his wrist.

“I was really at the end of my rope,” said Doolittle, who left Virginia with a school record 22 wins. “The decision really came out of wanting to extend my career. I didn’t want to look back in five or 10 years and have to wonder what might have happened. I didn’t want any regrets.”

He was close to making it as a position player and was set to return to the A’s Triple-A affiliate in Sacramento before making the switch.

Just about the time Melvin was introduced as the A’s interim manager, Doolittle rebooted his baseball career as an interim pitcher.

“It is not lost on me on how crazy it is,” Doolittle said. “I’ve seen enough guys in Triple-A who spend their whole careers there and couldn’t catch a break. I’ve been here two years and we have two division titles. I still take nothing for granted.”