MILWAUKEE -- The Astros have a few red-hot bats a phone call away at Triple-A Round Rock. Third baseman Chris Johnson, who began the season on the Astros' roster, is hitting .373, center fielder Jason Bourgeois is hitting .350 and left fielder Brian Bogusevic is hitting .306.

In Tuesday's win over Las Vegas, Johnson went 1-for-4 with a homer, Bourgeois was 2-for-5 with an RBI and Bogusevic was 3-for-5 with two runs and an RBI. Infielder Matt Kata went 4-for-4 with three RBIs in the game.

Astros assistant general manager Ricky Bennett said Minor League field coordinator Dick Scott is in Round Rock watching the Express and raved about Bogusevic and Johnson.

"Compared to where he was a month ago when Dick last saw him, he said Bogusevic is really, really making a lot of progress offensively," Bennett said. "He's hitting the ball to all parts of the field and is really driving the ball. He's got better plate coverage and he's making a lot of progress.

"C.J. is swinging the bat well, too. Having that injury [right intercostal strain] early in the season, it kind of slowed him down, but now he's got some at-bats under his belt and he's starting to put things together like he did in Spring Training."

Bennett said Bogusevic and Johnson have put themselves in position for callups down the road.

"That's something we've talked about here recently," Bennett said. "I don't think we're at the point yet, but if they continue to make progress the next month to six weeks, we have to give them consideration to have an opportunity to play here."

Berkman slips to fifth in lineup

MILWAUKEE -- In an attempt to get his lineup going against a left-hander Wednesday, Astros manager Brad Mills flip-flopped first baseman Lance Berkman and right-fielder Hunter Pence, with Berkman hitting fifth and Pence hitting third. It's the first time Berkman has hit fifth since June 27, 2009.

"I'm not saying we're going to do it all the time against left-handed pitchers, but I thought this might give us a little balance," Mills said. "I talked to both guys and they understood what we're trying to do, and we'll see how it works."

Berkman is hitting .176 (3-for-17) this year against lefties, and Pence is hitting .310 (9-for-29).

"Hunter's hitting really well against left-handed pitching, so it's a different look," Berkman said. "It's not like any of us are hitting the ball. It really makes no difference at all [where he hits]."

Pence was hitting .317 with five homers and 13 RBIs in 15 games prior to Wednesday to raise his average to .252.

"He's definitely gone deeper in counts," Mills said. "What he's doing, he's giving himself a chance to get better pitches to hit as he goes. I have seen that. He's starting to hit a few home runs and drive the ball the other way, which is really nice."

Sampson aims to get past rough outings

MILWAUKEE -- Coming off a pair of rough outings in which he gave up seven runs in 1 1/3 innings, right-hander Chris Sampson arrived early to Miller Park on Wednesday and went to work. He did his physical exercises before sitting down with pitching coach Brad Arnsberg for a lengthy video session in the clubhouse.

Sampson had posted a 1.06 ERA in his 18 outings prior to Sunday.

"It's one of those things, in my opinion, all baseball players at some point in time are going to go through a slump, and my last two outings haven't been so great for me," Sampson said. "If I am in a slump, I didn't want it to last too awfully long.

"I'm just doing everything I can and working my tail off and trying to not repeat any mistakes I'm doing and try to find out what he's seeing, trying to work with him and get through this thing together. It's two bad games in a row for me, and I don't want to have a third."

Sampson lauded the work Arnsberg puts in studying video of opposing pitchers and the mechanics of his pitchers.

"He's a computer genius," Sampson said.