Injury updates and more on Hart's promotion

BOSTON - On a relatively slow news day so far, here are a few injury updates related to the Orioles:

* Pitcher Gabriel Ynoa, on the disabled list with a right shin stress reaction, is undergoing an MRI today on his right shoulder. His condition hasn't spread. This is something unrelated.

"The shin seems to be doing well," said manager Buck Showalter, "but he's had some shoulder issues."

* Left-hander Chris Lee, who sustained an oblique injury while facing his only batter in spring training, will throw a bullpen session on Saturday.

"That's a good sign," Showalter said. "First time he's been up on the mound."

* Left-hander Ryan O'Rourke, recovering from Tommy John surgery, will throw live batting practice on Saturday.

"That's good to hear," Showalter said.

* Infielder Ryan Mountcastle, who sustained a hairline fracture in his right hand in March, has been cleared for all baseball activities except hitting. Throwing, fielding and runner are allowed.

"Hopefully, that will get cleared before too long," Showalter said.

Showalter explained the decision to recall left-hander Donnie Hart for the Red Sox series that begins tonight.

"He's been pitching well," Showalter said. "He's obviously on the (40-man) roster, but he was, we thought, our best option at this point. Donnie's been throwing the ball well. Really been aggressive and went after guys down there.

"When you say things to a guy when he leaves and he goes and does what he's supposed to do and we knew we'd probably need somebody at some point ..."

How did Hart lose that aggression that's now resurfaced?

"I think anytime you have failure up here early - I ran into some of it last year - you kind of get a little tentative," he said.

"It's easy to do that. I think I got away from that. I had a couple outings that weren't so good and then you go back out there and you have them in the back of your head. Sometimes, it's a little easier said than done to throw them away and move on from them, but I think that was one of the biggest things.

"You can't get those outings back, so you've got to move on to the next day and that was one of the things that I had to run through my head a lot as spring training went on and as the season started down there."

Hart gives the Orioles a fourth reliever who can be optioned without passing through waivers. The flexibility is appreciated, but not a requirement.

"That's part of it," Showalter said, "but I'm not going to sit here and say the only reason we took Donnie was because he's on the roster. We thought he was the best guy who also happened to be on the roster.

"We're able to kind of mix and match some about the needs. We're getting ready to face a club (Tigers) next that's only got one left-handed hitter. If you can get ahead of things like that, it helps you put your best foot forward. It also helps you protect the other people in your bullpen."