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9/2/2013 9:16 P.M. ET

Corporan progressing toward return from concussion

HOUSTON -- It's common practice for teams to add a third catcher when rosters are expanded in September, and Astros manager Bo Porter would definitely like an extra backstop at some point soon. That's probably going to be accomplished when Carlos Corporan comes off the disabled list.

Corporan is one of two Astros catchers on the 7-day disabled list for concussions, along with Max Stassi. Corporan, who was hit in the face mask on Aug. 19, is increasing activity daily and still needs to pass his baseline tests to return.

It's still to be determined if Corporan would need some at-bats in the Minor Leagues.

"That's not a decision we've made yet," Porter said.

Porter is mindful of the workload of starting catcher Jason Castro, who has set career highs in games played (117) and at-bats (424). Porter has started at designated hitter 16 times this year in an effort to keep him fresh.

"As much as we've been able to take care of Castro this year, this last month we need to make sure we can continue that same pattern and keep him fresh and keep him finishing throughout the course of the year," Porter said.

Castro injures knee, will see doctor on Tuesday

HOUSTON -- Already short-handed at catcher, the Astros lost starter Jason Castro early in Monday's game against the Twins.

Castro was pulled from the game after an RBI single in the second inning with a sprained right knee -- the same knee he had surgically repaired in 2011. This injury, suffered while he was running the bases in the first inning, isn't believed to be serious because Castro left the ballpark without the aid of crutches or wearing any kind of brace.

The Astros will update his condition after he's seen by a team doctor on Tuesday.

"Obviously, they're going to give us their best evaluation, and then we'll talk to Jason and go from there," manager Bo Porter said.

Castro, an All-Star this season and two-time American League Player of the Week, is having a career season, hitting .282 with 18 homers and 56 RBIs after going 2-for-2 with two RBIs on Monday.

The Astros have two catchers on the seven-day concussion disabled list -- Carlos Corporan and Max Stassi. Corporan was injured Aug. 19 when he took a foul ball of his facemask, and Stassi was hit in the head by a pitch two days later and hasn't played since.

Cody Clark, a 31-year-old who was called up Aug. 23 after 11 years in the Minor Leagues, replaced Castro and went 0-for-3, dropping him to 0-for-13 for the season. The Astros didn't call up a third catcher when rosters expanded. Their Triple-A affiliate in Oklahoma City and Double-A affiliate in Corpus Christi are both going to the playoffs.

Porter shuffles batting order against Twins

HOUSTON -- After first settling into a lineup that included Robbie Grossman in the leadoff position, L.J. Hoes in the second spot and Jose Altuve in the third spot, Astros manager Bo Porter slipped Hoes into the eight-hole for the second game in a row Monday.

Hoes entered Monday in a .138 slump (4-for-29), which played into Porter's decision to bat him eighth. He's hitting .351 (13-for-37) at No. 8 in the batting order this year. Altuve batted second Monday for the first time since Aug. 4. He had hit third the previous 18 games.

"He's hit a snag a little bit, and I wanted to get him out of the two-hole and get Altuve in the two-hole, and get Jason [Castro] in the three-hole," Porter said. "It was a multitude of things that went behind it. Altuve has hit second this year, he's hit third and he's hit first. Hoes has had success in the eight spot as well."

Altuve has had his most success hitting leadoff this year (.326), but Porter likes Grossman in that spot because he has a higher on-base percentage. Grossman has a .340 on-base percentage in the 33 games since he returned to the Majors on July 28.

Worth noting

• Astros outfielder J.D. Martinez, who's been on the disabled list since July 27 with a left wrist sprain, is taking live batting practice while working out in Kissimmee, Fla., and should be back before the end of the regular season, Porter said.

• Hall of Fame broadcaster Milo Hamilton, who had called Astros home games through the end of last season, celebrated his 86th birthday on Monday. He was at the ballpark and was recognized during Sunday's game.

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.