Jason Hammel

Orioles pitcher Jason Hammel throw from the mound after hurting his knee in the fourth inning, but he was taken out of the game. (Lloyd Fox, Baltimore Sun / July 13, 2012)

The Orioles won’t know the extent of starting pitcher Jason Hammel’s injury until Saturday afternoon, when he gets a MRI on his right knee.

But there is cause for concern, considering Hammel was forced out of Friday’s 7-2 loss to the Detroit Tigers in the fourth inning because he felt pain – in the same area of the knee that has bothered him much of the season.

“I was driving toward the plate and it didn't feel good. Something felt really bad. It's the same area as the injury was before,” Hammel said through a club spokesman while receiving medical treatment. “It's kind of just day to day. We scheduled an MRI for [Saturday] and we'll find out more, but as of right now, we don't really know what's going on here.”

Hammel, who is 8-6 with a 3.54 ERA, has emerged as the club’s ace despite pitching through the balky knee. Orioles manager Buck Showalter has tried to give him extra rest when possible, but now the Orioles are looking at playing 29 games in the next 30 days. So if Hammel can’t pitch, he’ll have to go on the disabled list. That’s a little premature for now, though.

“He's had some pitches he's thrown this year where it bit him a little bit and then went away. This one didn't go away. He's got an MRI scheduled tomorrow at 1 o’clock to get an idea so we can compare it to the last one, see if anything’s changed in there,” Showalter said. “The good news right now is it doesn’t seem to be swelling, which is usually indicative of something. We’ll take that as good news and see what the tests show tomorrow.”

Hammel, along withWei-Yin Chen, has been one of only two consistent Orioles starters this season. How devastating would it be if the Orioles lost him for several weeks?

“That would be a huge [blow] for us. He has been our horse all year,” Chris Davis said. “Obviously, tonight we didn’t give anybody a lot of run support, no matter who – Hammel or who came out of our bullpen. But to lose a guy like that at this point in the season would be really tough.”

Said Showalter: “Hamm's a tough guy and he's posted up for us. It's something at the end of the season, we're thinking we're going to have to do something with it anyway, but we felt like we could manage it the way we were managing it. Hopefully, we'll get some good news and continue down the path we've been with him and his knee.”