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9/7/2013 3:42 A.M. ET

Astros taking caution with Grossman's injury

OAKLAND -- Astros outfielder Robbie Grossman has yet to pick up a bat and remains day-to-day as he recovers from a strained oblique incurred while swinging in the 12th inning of Tuesday's contest against the Twins.

Friday was his third game out of the lineup since the injury, and manager Bo Porter said it's still unclear when Grossman will be able to return.

"He's still a little sore," Porter said. "Again, those obliques can be funny. I think we just have to monitor it each and every day and see how he progresses."

With the nature of the injury, combined with the team's place in the standings and the limited amount of games left in the season, Porter wasn't ready to determine whether Grossman will return before the season's end.

"I don't think we can sit here today and make that prediction," Porter said. "I think as time goes on, he's going to get treatment, and once he's physically able to play, we'll get him back in there.

"The luxury we have is this is September, so there's no sense of putting anybody on the DL. You're not in jeopardy of playing with a short roster, so we'll give him the time that he needs and let the trainers do what they need to do, and hopefully he gets back healthy and gets back out there."

Barnes ejected in sixth inning against A's

OAKLAND -- For the second time in as many games, someone in the Astros' dugout was ejected.

Brandon Barnes was tossed in the sixth inning Friday night with Houston trailing, 5-4, after arguing a call with home-plate umpire Alan Porter. The Astros' center fielder was hit by a pitch from A's right-hander A.J. Griffin but was denied first base after Porter ruled that Barnes didn't make enough of an effort to avoid the ball. Barnes, who leads Houston with seven hit-by-pitches this season, eventually struck out swinging.

"He told me I leaned over and I leaned into it," Barnes said. "That's a judgment call. So I went back to the dugout."

Barnes disputed the call at the plate and continued to express himself in the dugout and eventually was ejected. The ejection was Barnes' first of the season.

"I was at the bat rack and I was yelling at the bat rack, and I guess he heard something," he said. "I wasn't deliberately yelling at him. Again, it's a judgment call."

Astros manager Bo Porter was ejected in the eighth inning of Houston's 3-2 win on Thursday after arguing a tag play at home plate.

Clark contributes on defense while awaiting first hit

OAKLAND -- Cody Clark, Houston's 31-year-old rookie catcher, is hitless in 19 at-bats since making his Major League debut on Aug. 23, but he's still finding ways to contribute for his team.

Clark has thrown out six of eight would-be base stealers in six games this season, and he received another opportunity to notch that elusive first big league hit with his fifth career start on Friday night but went 0-for-2.

"I just want to get it out of the way and get it past me so I can stop thinking about it," Clark said before the game. "I'll take anything I can right now."

The amount of time it takes to get that first hit varies, obviously. Using the Astros' opponent as an example, outfielder Michael Choice recorded his first hit in his second-career start this week with a dribbler toward the mound, while catcher Stephen Vogt required 28 at-bats, extending to last year, before finally getting that first hit -- a home run -- this season.

"As soon as that first one comes, hopefully the floodgates will open a little bit," Clark said.

Whenever it comes, Astros manager Bo Porter said he isn't too concerned with Clark's cold streak to start out. Clark's first priority is calling a good game, Porter said. Production at the plate is secondary.

"He's done a tremendous job of calling games, he's done a tremendous job of throwing the baseball," Porter said. "I tell all the catchers each and every time they go out to catch a game right before the game: I don't say get three hits. I don't say drive in four runs. I tell them to catch a winner. And as a catcher, that's your No. 1 job."

Castro, Dominguez back in starting lineup

OAKLAND -- Jason Castro and Matt Dominguez returned to the Astros' starting lineup on Friday night against the A's after recovering from ailments that had kept them sidelined since Monday.

Castro, Houston's All-Star catcher who sprained his right knee Monday, batted cleanup as the team's designated hitter as he continues to recover a cyst he got when he fouled a ball off his knee. Dominguez was fifth in Friday's lineup and back at third base after missing time with a sinus infection.

"I was pretty disappointed to have to sit out the past few days, but I'm thankful it was only a few days and not more," said Castro, who missed the entire 2011 season following surgery to repair the anterior cruciate ligament in his right knee. "Everyone's goal right now is to finish out as strong as possible and go into the offseason with as much confidence as we can, so we can build on that and hit the ground running come Spring Training next year."

Dominguez first began feeling dizziness Monday and was given antibiotics to help relieve his symptoms. He said he's not at 100 percent, but he's well enough to play.

It will take a few more days before Castro can return to catching. The first hurdle, he said, was to be able to hit in some capacity for the team. He took batting practice Thursday without complications but felt tentative about running on the injury, which he said wasn't a concern Friday. Squatting and catching activities are soon to follow.

"I'm pretty happy with the way everything has gone on," Castro said. "I'm feeling good and hopefully it'll continue to keep improving and get back to 100 percent."

Jeff Kirshman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.