SEATTLE -- Josh Hamilton began the 2014 season as one of baseball's hottest hitters, picking up where he left off to finish an otherwise miserable first year with the Angels and looking a lot more like the five-time All-Star from Texas.

Then he decided to slide headfirst into first base, and now he could be out until June.

An MRI Wednesday morning on Hamilton's left thumb, which he banged against first base in the seventh inning at Safeco Field the night before, revealed that he suffered a complete tear of the ulnar collateral ligament along with a torn capsule.

The 32-year-old outfielder has already been told by the Angels' medical staff that he will need to undergo surgery, which carries an estimated recovery time of six to eight weeks, but it won't be official until he meets with hand specialist Dr. Steven Shin on Friday.

"Any time you play and you're playing hard and you're having fun, the last thing you want to do is do something that's going to cost you to miss time and maybe hurts your team in the long run," Hamilton said prior to Wednesday's game against the Mariners. "If I could see a future, obviously I wouldn't do it. But in the moment, when my mind and my body tells me to do something and react some way, I've always done it. That's what I do. You can't change that."

With Hamilton on the disabled list, outfielder J.B. Shuck has been recalled from Triple-A Salt Lake.

Raul Ibanez was given the day off for the finale of a six-game road trip, prompting Kole Calhoun to slide into the No. 6 spot and Collin Cowgill to lead off and play left field. But Angels manager Mike Scioscia indicated that he'd keep Calhoun leading off most nights, with Albert Pujols, David Freese and Ibanez making up the middle of the order. Moving Mike Trout from second to third isn't in the current plans.

Scioscia, who isn't a big fan of Hamilton sliding headfirst into first base, said, "You never want to coach the athleticism out of a player.

"Certainly you wince when you see a guy going headfirst into home plate or first base, because it's something that is not as natural as other plays around the field. But he's done it a hundred times in his career. This is the one that caught his thumb."

Hamilton -- delayed earlier in Spring Training because of a strained left calf -- looked primed for a bounce-back season early on, entering Tuesday's game with a .500 batting average, a couple of homers and a team-leading six walks.

Then he slid headfirst while getting thrown out on a slow roller to the left side in the seventh inning Tuesday, had trouble throwing in the outfield, didn't feel good taking dry swings in the batting cage and told Scioscia to pinch-hit for him with two on and none out in the ninth inning of an eventual 5-3 loss.

"When I got in the dugout [after the slide], it didn't feel like anything different than I've had before in terms of a jammed finger," Hamilton said. "When I went out to the outfield and gripped the ball and threw the first three 30 feet to the left of where I was aiming, that was an indication something might be wrong."

Hamilton had never suffered a thumb injury and is relieved that the surgery will occur on the left hand, which only guides the bat of a left-handed hitter, rather than the right one, which acts as a base and provides the power. In the early stages of his rehab, Hamilton anticipates being able to work out and do plenty of hitting drills with one hand, in hopes of not losing much of the promise he was showing this season.

"I don't plan on being as far behind as people think I'll be," Hamilton said. "Everyone thought I'd be far behind in Spring Training without as many at-bats. It'll be good."