Josh Hamilton had a feeling his mad dash home was a mistake.

The Texas slugger was right, and now his Rangers are really hurting.

Hamilton is expected to miss six to eight weeks after breaking his upper right arm on a headfirst dive into home plate Tuesday, a play even he called "stupid."

The reigning AL MVP was on third base, having just made a headfirst slide on an RBI triple in the first inning against Detroit, when Adrian Beltre lifted a foul pop near the Tigers' dugout.

Third baseman Brandon Inge and catcher Victor Martinez both chased the ball, leaving the plate unprotected. Inge made the catch, Hamilton tagged up and took off. Inge tossed to Martinez, who scampered back in time to tag Hamilton.

"It was a stupid play," Hamilton said. "The whole time the ball was in the air, the coach was yelling, 'Go, there's no one at home,' and I was thinking, 'I don't want to do this, something is going to happen.'

"But I listened to my coach," he said, referring to third-base coach Dave Anderson. "It was way too aggressive. Maybe if they had both been closer to me, but they had a perfect angle to cut me off, and the only way to avoid a tag in that situation is to go head first."

After the Tigers' 5-4 win, Rangers general manager Jon Daniels defended Anderson's decision to send Hamilton.

"We play an aggressive style of baseball," he said. "The chances of getting hurt on that play are minimal."

The AL champion Rangers, off to a 9-2 start, said Hamilton has a non-displaced fracture of the humerus bone at the top of his arm, just below the shoulder. He isn't expected to swing a bat for a month.

The fracture was small enough that it wasn't detected on an X-ray, but Daniels held a conference call about two hours after the game with results from an MRI exam.

"Obviously, he's a big part of our club," Daniels said. "We built the club to deal with something like this."

Texas manager Ron Washington was actually giving Hamilton a breather Tuesday by making him the designated hitter instead of starting him in the outfield. Washington said before the game he planned to give Hamilton the day off entirely on Wednesday.

Now, Hamilton's headed to the disabled list, and Daniels said the team will probably call up Chris Davis from Triple-A Round Rock.

Hamilton missed most of the final month of the regular season last year with two broken ribs after he made a catch, then rolled his ankle and stumbled hard into the outfield wall at Minnesota. He was back in time for the postseason and helped Texas reach the World Series.

Hamilton hit .359 with 32 home runs and 100 RBIs in 2010. He's hitting .333 this season.

In 2009, Hamilton was limited to 89 games when he had two stints on the disabled list after separate wall-crashing catches.

The Rangers gave him a $24 million, two-year contract in February that avoided arbitration.