ST. PETERSBURG -- The Orioles claimed right-handed pitcher Josh Stinson off waivers from the Oakland Athletics on Thursday, optioning the right-hander to Triple-A Norfolk to add to their pitching depth.

"Stinson is a 25-year-old, very capable Major League pitcher who pitched well for Milwaukee last fall and again this spring," said executive vice president of baseball operations Dan Duquette, who added that the plan was for Stinson to be a starter.

Stinson joins a Triple-A rotation that also includes Zach Clark, Jair Jurrjens, Zach Britton and newly signed Freddy Garcia. The A's selected Stinson off waivers from the Brewers on March 29, and in 10 Spring Training games for Milwaukee, Stinson allowed four runs (two earned) and 10 hits in 12 innings, with eight walks and five strikeouts.

To clear a spot on the 40-man roster, the Orioles transferred pitcher Tsuyoshi Wada to the 60-day disabled list. Wada, who is rehabbing from Tommy John ligament replacement surgery on his left elbow, is targeting an early June return.

Roberts exits game with hamstring injury

BAL@TB: Roberts appears to injure leg while sliding

ST. PETERSBURG -- Brian Roberts exited Thursday's game against Tampa Bay in the top of the ninth inning with a right hamstring injury, and he will have an MRI exam on the area Friday.

"Somewhere in the last couple of steps, I felt something kind of pop in the back of my knee," said Roberts, whose exit put a damper on the Orioles' 6-3 win. "I don't know what happened exactly."

Roberts stole second base but came up and grabbed the back of his right knee in pain and was helped off the field by head athletic trainer Richard Bancells and first base coach Wayne Kirby. The 35-year-old Roberts, who has dealt with a host of injuries and has not played a full season since 2009, said it was his first hamstring injury, and he was understandably down about the injury.

Asked how he felt mentally, Roberts said: "Not too great. I don't know. I don't have a whole lot of words for it right now. Frustrated, but we'll get the results and hopefully move forward."

Roberts worked hard to be a full-go this spring and had looked to be more of his old self in the field and at the plate. He is hitting .417 in three games, batting ninth for the Orioles in their season-opening series, and had been looking forward to suiting up in Friday's home opener.

"Dr. [John] Wilckens will see him tomorrow," manager Buck Showalter said. "That's a quick turnaround. Not going to say he's going to be able to play tomorrow. We'll reassess it tomorrow and see where we are. He's in some discomfort."

While it's still early to be speculating on a possible trip to the disabled list for Roberts, the Orioles do need to make a roster move to clear a spot for starter Chris Tillman on Saturday. Should Roberts be sidelined, Alexi Casilla -- who took over Thursday -- figures to get the bulk of the playing time at second base.

"He's been struggling for the past three years," Thursday starter Miguel Gonzalez said of Roberts. "And he's a great, great teammate. Battles, plays hard and that's what you want in a teammate; I hope he comes back quickly. And I think he will. He said he's hurting a little bit, but he will be back."

Homer by homer, Davis' power on full display

BAL@TB: Davis opens scoring with two-run shot

ST. PETERSBURG -- Orioles first baseman Chris Davis hit his third home run in three games Thursday afternoon, continuing his torrid pace to start the 2013 season. And according to Elias Sports Bureau, he's the first player with three or more RBIs in each of his team's first three games.

Davis, who has homered in nine of his last 10 regular-season games dating back to last year, said the ability to play every day over a full season was huge in his development as the 27-year-old has found a starting spot with Baltimore.

"[I] learned a lot about myself as a player, what it took for me to get ready every day," said Davis, who played in a career-high 139 games last year, hitting a team-leading 33 home runs. "And I pride myself on working hard in the offseason, obviously weight-training, and did a few other things to try to sharpen some other tools, [like] speed.

"At the end of Spring Training I felt comfortable in the box. The ball I hit against the Mets that last day was probably a telltale sign, drove the ball the other way. That's usually when I'm going good. So, I'm not going to read too much into it, just keep doing my routine and hopefully keep swinging the bat."

According to Elias Sports Bureau, Davis joins Frank Robinson (in 1966) as the only players with home runs in each of the first three games of the season for the Orioles/Browns franchise since 1920.

Davis, who has 11 RBIs, has been so locked in that Tampa Bay manager Joe Maddon joked following Wednesday's game that the team was not going to pitch to him, but rather just roll it in. And while he was not walked, Davis did take a pitch to the right leg in his second at-bat Thursday in the fourth inning.

"I'm not a big believer in changing a lot of things," Davis, who was acquired in a midseason trade with Texas in 2011, said of his approach during a hot streak. "The biggest thing for me is to keep the consistent approach and stay positive. The game is hard enough as it is without us having to make it any harder.

"One of the things I learned going up and down in the Rangers' system was, there were times when physically I felt good and mentally I just wasn't there. Whether it was I wasn't being aggressive enough or I was being too aggressive. I think I got in my own way sometimes. I was able to learn from that and thankfully not have it be the end of me."

Betemit's surgery unlikely to delay recovery

BOS@BAL: Betemit injures right knee, carted off

ST. PETERSBURG -- Wilson Betemit had arthroscopic surgery Wednesday on his right knee, a procedure done by team orthopedist Dr. John Wilckens in Baltimore and one that was not expected to alter Betemit's timetable.

"He's doing well," Orioles manager Buck Showalter said of Betemit, who was diagnosed with a Grade 2/3 posterior cruciate ligament tear sustained in a game March 25. "PCL looks like it's going to heal. A couple things they just kind of cleaned up a little bit, but nothing major. Nothing from the procedure will set back his recovery time. Everything they were hoping to find they found."

Betemit is not sure what caused the injury -- which came while he was running back from second base -- but it was a frightening sight as his knee buckled and he went down to the ground. He was carted off the field and told reporters the following morning that his recovery time would be six to eight weeks.

"I did not ask if that means, 'Does that mean he's playing in a Major League game then, or before he starts baseball activities?'" Showalter said. "I just know we aren't going to be thinking about him before that time period. It could come a little quicker. But they don't think it will be longer than that. If it comes a little quicker, he could start baseball activity a little more. If you eyeball the injury and everything, it's really a positive thought to think he's going to be playing full speed. I just love the fact that he didn't really have to have any major surgery, should recover. I would never have dreamed that when it first happened."

O's remain optimistic on Bundy's outlook

TB@BAL: Bundy pitches three innings in relief

ST. PETERSBURG -- Orioles top pitching prospect Dylan Bundy threw Thursday with no reported issues, and the organization remains optimistic that it is a minor issue with Bundy, who was placed on the Minor League disabled list with tightness in his right forearm/elbow.

Bundy, who will start the season with Double-A Bowie, is on the seven-day DL in the Minor Leagues. The 20-year-old appeared in four big league games this spring before he was optioned, and his velocity was down from last year along with some mechanical issues that Bundy said caused him to be a little "out of whack." The Orioles will proceed cautiously with Bundy, who ascended to the Majors in his first full pro season last year.

Right-hander Steve Johnson (right lat strain) began a throwing program Wednesday at the team's spring complex in Sarasota. Johnson is expected to start the season at Triple-A Norfolk when deemed healthy.