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5/29/2013 9:27 P.M. ET

Clemens comfortable with role in bullpen

DENVER -- A starter for much of his career in the Minor Leagues, right-hander Paul Clemens has gotten comfortable as a reliever in his first year in the Majors. Clemens entered Wednesday with a 2-2 record and a 4.35 ERA in 31 innings across 16 appearances.

"I feel like I've started to settle in the last two, two-and-a-half weeks," he said. "Knowing these guys can use me any time -- short, long, situationally. I've kind of settled into it and know every day I have to find a way to get my body fresh and be ready to pitch each night. My body has acclimated to it quickly and I like my role."

While Clemens uses the hot tub and various exercises to try to ensure his velocity and mechanics are in top shape daily, the mental aspect of being ready to come to the ballpark on a daily basis with a chance to pitch has taken a few adjustments as well.

"Whatever I did on that fourth or fifth night as a starter to get ready to pitch, I'm doing that every night, which is relaxing and focusing on success and doing the little things I can to stay mentally fresh and prepared," he said. "That phone could ring any night."

Astros manager Bo Porter uses Clemens in a "flex" role, meaning he could use him in long relief and just for an inning or less.

"We use him both ways and he's been successful in each one of those ways, and it's like it's a game-by-game situation," Porter said. "We will not leave him down there long without throwing."

Porter looking to establish regular lineup

DENVER -- The Astros' lineup will likely remain a work in progress as long as they remain knee-deep in their rebuilding process, though some spots have slowly worked themselves out. The Astros used 45 batting orders in their first 52 games.

With outfielder Robbie Grossman in Triple-A Oklahoma City, Brandon Barnes is getting more of the playing time in center while leading off. Manager Bo Porter likes Jose Altuve in the No. 2 hole, Jason Castro at No. 3 and lately J.D. Martinez in the clean-up spot.

The fifth and sixth spots alternate between Carlos Pena and Chris Carter. Porter also likes Matt Dominguez in the eighth spot, though he was hitting seventh in a National League ballpark Wednesday so veteran Ronny Cedeno could hit eighth in front of the pitcher.

"I try to do everything I can to put guys in positions I believe they are going to be successful," Porter said. "I want to have continuity as much as we can, but at the same time, when roster moves are made or changes are made, you have to adjust to those changes being made."

Porter said established teams like Detroit, which has Torii Hunter hitting second, Miguel Cabrera third, Prince Fielder fourth and Victor Martinez fifth almost each night, have a luxury the Astros don't have at this point.

"They run the same guys out there every day," he said. "Our guys have not established themselves to that point, and that's what we're working through."

Worth noting

• Astros manager Bo Porter said shortstop Marwin Gonzalez is dealing with a sore hamstring. Porter said Gonzalez was given the OK to play, but he wants to give him an extra day out of the lineup, though he's available in an emergency if needed.

Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.