HOUSTON -- Astros manager Brad Mills swapped the usual batting slots of rookies Jason Castro and Brett Wallace on Friday, placing Castro at No. 6 and Wallace at No. 8 in the lineup, hoping to give the slumping Wallace a "jump-start".

Wallace has spent the majority of his brief Major League career in the No. 6 spot (64 of 97 total at-bats), but he's hitting just .156 there. Wallace did, however, launch his first career home run on Tuesday, and Mills is hoping a change in lineup scenery can expedite his development.

"We're hoping -- whether it's pressure or something else -- that [Wallace] will get different looks down there," Mills said. "It's the same for Castro. We're just moving those guys around to try and get a different look, to see if they can get jump-started a little bit."

Though Castro has slumped at the plate for much of his rookie season, the catcher has turned into a force in September, hitting .333 with a .412 on-base percentage, justifying a move higher in the lineup.

"I try not to focus on that," Castro said. "You don't really try and look at anything extra, other than what you can control. I just take my at-bats as they come and focus in on them and that particular situation."

Castro went 0-for-3 and Wallace was 2-for-3 with a double in Friday's 4-2 loss in 11 innings to the Dodgers.

Paulino feeling fine day after simulated game

HOUSTON -- Right-hander Felipe Paulino reported no ill-effects a day after throwing his second simulated game, and the Astros are still hoping for his return before the end of the season. Paulino threw about 45 pitches in two innings on Thursday, but both he and manager Brad Mills had said they would exercise caution until they saw how Paulino's arm responded on Friday.

"I feel good," Paulino said. "I'm a little sore today, but nothing out of the ordinary for a day after pitching. It's a good step for me. The last two months have been tough."

Mills said the next step for Paulino had yet to be determined, but the Houston manager characterized the latest simulated game as "good progress" in Paulino's recovery from the right shoulder tendinitis that has sidelined him since June 21.

"He wants to get back out there," Mills said. "The important thing here is to get him some confidence, to get back on the mound and throw. That's what he needs to think of before the end of the season."

Paulino had an ERA of 4.40 in 14 starts prior to the injury. Should he return in 2010, Mills has said it would likely be in a relief role.

Astros digging deep for wins in September

HOUSTON -- The Astros haven't been a powerful club in 2010, ranking 28th in the Majors in home runs entering Friday. But they've had a way of making their homers count in September, with a three-run blast representing the winning margin in four of Houston's six wins in the month.

The latest dramatic home run came courtesy of rookie third baseman Chris Johnson on Thursday. Johnson's three-run shot in the bottom of the sixth erased a 2-0 deficit, sending the Astros to a 3-2 win over the Dodgers and pushing Houston to a 6-2 mark in September.

"When you're not scoring a lot of runs and you're not giving up many runs, any instant run is going to be really important," Astros manager Brad Mills said. "I think that's what you're seeing."

Indeed, the Astros' 2.31 ERA since Aug. 13 led the Majors entering Friday's action. As a team, Houston's 19-8 record since then is tops in the National League.

Astros, fans attempt world harmonica record

HOUSTON -- The Astros and their fans attempted to set a Guinness world record on Friday for the largest harmonica ensemble following the team's 4-2 loss to the Dodgers in 11 innings at Minute Maid Park.

Harmonicas were distributed to 10,000 fans in attendance, who were taught to play a song by several celebrated harmonica players in video tutorials after the game. The current record of 6,131 was set by a group from Hong Kong in 2009.

An official adjudicator with the Guinness Book of World Records was in attendance to certify the feat, but official word of a new record was not immediately determined.

The Astros came up with the idea alongside producers of the independent film "Pocket Full of Soul: The Harmonica Documentary", which features performers including Clint Black, Huey Lewis and Taylor Hicks.

The version of "Take Me Out To The Ballgame" played during the seventh-inning stretch was also conducted with the harmonica.

Astros manager Brad Mills said before the game that he wouldn't be surprised if some of his players took part in the production, but joked that he wasn't interested himself.

"I try to use my hot air in other places," Mills quipped.

Worth noting

Hall of Fame radio announcer Milo Hamilton will miss the Astros-Dodgers games over the weekend to attend his 65th high school reunion in Fairfield, Iowa. He will return on Monday when the Astros host Milwaukee. ... Including Thursday night's win, the Astros are 8-1 in right-hander Bud Norris' last nine starts. ... Closer Brandon Lyon's 15-inning scoreless stretch is the second-longest active streak in the NL. ... Entering Friday, the Astros had won five of six, eight of 10 and 14 of their last 17 games.