Watching from the dugout as Brian Roberts clutched the back of his right knee Thursday, Ryan Flaherty knew an injury to the Orioles' starting second baseman could create an opportunity for him.

But his first feeling was concern for Roberts, who he says gave him invaluable advice as Flaherty manned second base for the Orioles in the playoffs last fall.

"It was tough to watch that, especially to have it happen to a player like him. He helped me tremendously last year playing second," Flaherty said Saturday. "He's been a great teammate. And to see him battle back then have a setback like this, it was tough."

With Roberts sidelined for three to four weeks with the ruptured tendon in the back of his knee, Flaherty made his second straight start Saturday night against the Minnesota Twins and batted eighth.

"Obviously, every time you get a chance to play, it's exciting, just to come out and help this team keep doing what it was doing the first three, four games of the season, help the team win," Flaherty said.

Flaherty batted .216 in 51 at-bats this spring with three home runs, four doubles and 10 RBIs.

He was hitless in Friday's 9-5 win over the Twins, but manager Buck Showalter wanted to give him another opportunity Saturday. Alexi Casilla will start at second base in today's series finale.

"We all know that Casilla runs better than Ryan. Ryan's got a little more pop," Showalter said when asked about their different skill sets. "I think they're both good defenders. They both throw all right."

Showalter indicated that he plans to give both players an opportunity to seize the starting spot until Roberts returns. A strict platoon is a possibility, but Showalter is not guaranteeing that.

Flaherty, who hit .216 with six home runs and 19 RBIs in 77 games last season, knows he can't take this next opportunity for granted as Roberts, his 35-year-old mentor, rehabilitates and works his way back.

"I felt like I had a pretty good spring," Flaherty said. "But now is when it counts."

McCutchen out 50 games

Right-hander Daniel McCutchen, whom the Orioles signed to a minor league deal this winter and was sent out of camp March23, has been suspended for 50 games for violating the league's drug policy.

According to a news release from Major League Baseball, McCutchen tested positive for methenolone and a metabolite of trenbolone. The suspension begins immediately.

Orioles executive vice president Dan Duquette declined to comment on the matter.

McCutchen, 29, was 1-0 with a 6.14 ERA in 71/3 innings over seven games this spring with the Orioles. On a suggestion by Showalter and pitching coach Rick Adair, McCutchen was attempting to reinvent himself as a sidearmer.

He was sent down to Triple-A Norfolk, where he allowed four runs in 12/3 innings over one appearance for the Tides (21.60ERA).

McCutchen spent parts of four seasons with the Pittsburgh Pirates, going 8-11 with a 4.77 ERA in 108 big league games (15 starts).

Tillman up, Navarro down

The Orioles activated Saturday's starter Chris Tillman from the 15-day disabled list before the game and optioned infielder Yamaico Navarro to Norfolk.

Navarro, a 25-year-old who was acquired in November in a trade with the Pirates, batted .276 in 29 at-bats this spring with three doubles and four RBIs. He also drew six walks.

Navarro was called up before Friday's home opener, but he did not play for the Orioles before being sent back to Norfolk. That happened with other players last season, but Showalter said veteran players in the minor league system such as Navarro know they could eventually get opportunities to play - and potentially stay - with the big league club.

"That's part of the reason why we were appealing to them," Showalter said. "They are aware of it. You always feel good anytime you can say something to a player and know that there's a chance it could happen. You wouldn't say it if you didn't."

Tillman was placed on the disabled list on March 28, retroactive to March 22, with a left abdominal strain.

O's protecting pitchers

With a 20-day stretch without an off day looming for the Orioles this month, Showalter said the plan is to stick with an extra pitcher and go with a three-man bench for the time being.

The Orioles will have off days on April 9 and April 15, but then they will play 20 straight days from April 16 to May 5. The first nine games will be at Camden Yards. The Orioles will then hit the road for 11.

"We're going to err on the side of carrying the arms, especially to protect the bullpen until guys kind of find their step as starters," Showalter said. "Rick (Adair) and I spend a lot of time, mostly seeing what Rick thinks, about protecting our guys' innings because we want to make sure we have all our bullets as we go through the season."

The bench Saturday consisted of Casilla, first baseman Steve Pearce and catcher Taylor Teagarden.

Showalter said the versatility of utility men Flaherty and Pearce - who is potentially the team's third catcher - and regulars such as Chris Davis, Nick Markakis and Manny Machado helps give the Orioles the flexibility to go with a three-man bench.

Around the horn

In the first four games of 2013, Davis had more RBIs (16) than 17 major league teams, and at least twice as many as six teams. He was the first player in Orioles history with a home run in each of the team's first four games and the first with at least three RBIs in each of the first four games. ... Showalter acknowledged that bullpens are a volatile commodity. "It's very unusual to have that many guys pitching at a high level last year," he said. But he isn't concerned with uneven early performances from the bullpen. ... Today's starter, Jason Hammel, is 2-0 with a 2.14 ERA in three career starts against the Minnesota Twins. Pedro Hernandez is scheduled to start for the Twins. ... Collectively, the Orioles have shown patience at the plate early in the season. Showalter said the fact that the Orioles have been getting production throughout the lineup has kept hitters from trying to do too much.

Baltimore Sun staff writer Dan Connolly contributed to this article.

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