When the Rays converted hard-throwing left-hander Jake McGee to a reliever three years ago, they knew he could eventually become a late-inning weapon.

The 6-foot-3, 230-pound former starter boasted a rising, mid to high 90s fastball, as well as a slow heartbeat that helped him command any moment.

But few could have foreseen how fast McGee, 26, would grow into his new role, as he put together one of the best years by a reliever in 2012, his first full big-league season.

His 1.95 ERA ranked third among American League relievers, and his .213 on-base percentage against was the best, even topping All-Star closer Fernando Rodney (.219). McGee held right-handed hitters to an .098 average, the lowest by a left-handed pitcher dating to 1974.

"He was unbelievably good," manager Joe Maddon said. "I mean, this guy nailed righties, very good against lefties, strike-thrower, doesn't walk people, calm. He did all those things.

"We thought he'd be good, but that was over-the-top good."

McGee said it was an accumulation of comfort, confidence and command. And though he may have exceeded expectations, pitching coach Jim Hickey believes that type of special season is sustainable.

"I think he's the kind of guy that can do that for a number of years," Hickey said. "And I also think he's a guy that can evolve into a later-inning, higher-leverage type of pitcher as well, whether that means the eighth inning, or whether that means the ninth inning, I think he's capable of both.

"He's capable physically, he's capable mentally and capable internally."