HOUSTON -- The Houston Astros aren't sure if they're going to make the postseason, but regardless of how the season ends, they're preparing for the best.

Playoff roster eligibility has to be set by Thursday night, and two position players -- infielder/outfielder Eric Bruntlett and catcher Humberto Quintero -- are now in that mix. They were recalled from Triple-A Round Rock on Monday, while J.R. House and Chris Sampson were optioned to the Express.

It's likely House and and Sampson will be back in 10 days, the minimum amount of time a player must stay in the Minors after he's sent down. That's one of the reasons why the Astros made the roster moves on Monday -- the off-day counts, and, including the four days leading up to Friday, House and Sampson can return to the team as early as Sept. 7.

"Plans can change, but that's the plan right now," general manager Tim Purpura said.

House and Sampson will not be eligible for the postseason, nor will any other September callup. Catcher Eric Munson will probably rejoin the team after rosters expand on Friday, and the Astros are talking about bringing up a few other role players -- some relief pitching and perhaps a player who can provide speed and defense. Round Rock outfielder Charlton Jimerson is being considered.

Pitchers expected to get a September callup may not be here right away. Round Rock and Corpus Christi are both set to go to the playoffs, and the Astros may wait before bringing in bullpen help.

"There will be some we'll need right away," Purpura said, referring to all players considered for promotions. "We narrowed it down and have a couple of pitchers we'll need at some point, not right away."

Bruntlett, 28, is a defensive whiz who can play seven positions. He hit .250 (23-for-92) with nine RBIs in 55 games for the Astros earlier this year, before he was optioned to Round Rock in early August. Quintero, 27, hit .298 (87-for-292) with four homers and 37 RBIs in 82 games for the Express this year.

Bruntlett was a major contributor defensively during the Astros' October run last year, and his presence on the postseason roster is essential. The Astros like Quintero's abilities behind the plate more than those of House or Munson.

"If we get into the playoffs and something happens to [Brad] Ausmus, we want the better defensive catcher to be here," Purpura said.

That doesn't mean the Astros will have only two catching options during the playoffs. Technically, they can put Jeff Bagwell on the postseason roster and then give his spot to a position player. Players on the disabled list can be substituted, as long as it's a pitcher for a pitcher and a position player for a position player.

The Astros begin a six-game homestand Tuesday with a 63-68 record and a four-game deficit in the Wild Card standings. They have 31 games remaining in the regular season and will play only one team -- Pittsburgh -- that is absolutely not in postseason contention.

The Astros host Milwaukee on Tuesday, followed by the National League East-leading Mets this weekend. They will then embark on another three-city road trip to play three contenders: Philadelphia, Milwaukee and St. Louis.