Lefties haven't been getting job done in bullpen

SEATTLE -- Astros manager Bo Porter admitted Wednesday he's concerned about the inability of his left-handed relief pitchers to get outs.

Kevin Chapman began the season as the only lefty in the bullpen, but he was optioned to Triple-A Oklahoma City after allowing seven walks, five hits and five earned runs in 3 2/3 innings. Veteran Raul Valdes was called up and has given up three walks, two hits and three runs in two-thirds of an inning.

"When you have just one [lefty] down there, they're down there for that specific reason," Porter said. "You would like to be able to bring them in the game and know that they're going to throw strikes. Whether or not you get the guy out is the second part of it.

"There's no defense for walks. You don't even get a chance of defending the ball. That's more so been our problem in that lefty-lefty matchup situation, is we're walking them on base and giving up hits after that, which is definitely not good."

That being said, Porter said he feels comfortable using right-handers Chad Qualls and Matt Albers against lefties.

"That's why we felt comfortable with just having one [lefty in the bullpen]," Porter said. "With that being said, even the one you have down there, they have to be able to win that matchup, left on left."