The inability of the Orioles' rotation to go deep into games claimed its first victim of 2011: left-handed reliever Clay Rapada.

The lefty specialist who was 0-0 with a 7.30 ERA in 22 appearances this season was designated for assignment Wednesday when the Orioles activated Alfredo Simon from the 15-day disabled list.

Although efficient against left-handed hitters, Rapada became expendable because the Orioles need to keep several long relievers around because of a rotation that has pitched seven full innings just once in 23 June games.

"Obviously, I think a lot of the move was dictated by [the fact] we need some length in the bullpen," manager Buck Showalter said. "And Clay, he did what he was designed to do statistically with left-handers, but we just weren't able to carry [a specialist]."

Although his overall numbers were ugly, Rapada was again strong versus left-handed hitters, who went 4-for-35 (.114 average) with one homer, three walks and 13 strikeouts against him. Because the bullpen was often depleted, however, Rapada was also forced to occasionally face right-handers, who were 9-for-13 (.692 average) against him with two doubles, one triple, two homers and three walks.

"It was a tough conversation," Showalter said about telling Rapada he had been designated. "You can look at the ERA overall, but you look at the numbers in the situation he is designed to do and you can see why he has been a chip for people that are playing late into October. So it'll be interesting to see how it develops."

The Orioles signed Rapada to a minor league deal this offseason, specifically because of how he has dominated left-handers in his career (.162 average against) and especially in 2010, when he gave up just one hit in 19 at-bats versus lefties while pitching for the American League champion Texas Rangers.

"You look at his background and who he pitched for and how he pitched last year — if you are in the right situation, your starters are going deep enough, you are able to carry someone like him," Showalter said. "We are just not in that position right now."

Jake Arrieta's seven-inning performance June 10 is the only time an Orioles starter has gone at least seven in a game this month. And only four times this month, heading into Wednesday, had Orioles starters gone at least 61/3 innings.

The club has 10 days to trade, ask waivers on or release Rapada outright. If he clears waivers, it would like to send him to Triple-A Norfolk, but because he has been outrighted to the minors previously, he can elect to become a free agent.

Assuming he was placed on waivers Wednesday — those moves are confidential — the club will know whether he cleared by 2 p.m. Friday, according to Showalter. Rapada was not available for comment.

Simon back from injury

When he was placed on the DL retroactive to June 13 with a right hamstring strain, Simon said he would return as soon as he could be activated. Technically, it took an extra day, but Simon was back Wednesday after throwing a scoreless stint Sunday at Double-A Bowie.

"I just pitched two innings in Bowie and feel ready, so I think I'm ready to go," said Simon, who is 1-1 with a 3.14 ERA in his first five appearances this year.

Showalter said Simon could be used in long relief or to help take pressure off setup men Jim Johnson and Koji Uehara in the late innings.

"He is able to do [long relief], and we are hoping that he can help us … from having to bring J.J. or Koji in too early," Showalter said. "Like all this, it's how deep we can go with the starting pitching."

Scott misses start

Outfielder Luke Scott, who bruised his right knee and jarred his ailing right shoulder while slamming into the left-field wall to rob Matt Holliday of a homer Tuesday, said his knee was still sore and somewhat swollen, but he felt he could pinch hit if needed Wednesday. Initially, he feared it would be worse when his knee smashed the piping that holds up the wall's padding.

"Imagine running into a pole playing basketball and hitting your knee. It's a contusion," he said. "The shoulder is a little sore. I felt that a little more [Wednesday] morning. [Tuesday] night, I didn't feel it because my adrenaline was going. I guess that's just part of it."