MILWAUKEE -- The Astros entered play Tuesday leading the National League with a .302 batting average with runners in scoring position, but they were hitting just .182 (4-for-22) with the bases loaded, which ranks 11th in the league.

Houston hitting coach Mike Barnett would obviously like to see greater production with the bases loaded, but he likes what he's seen with runners on third base and less than two outs.

"We're picking up those runs and doing good things," he said. "The big thing to our guys is to try to stay with the same mindset, the same approach that you have with nobody on base. It really doesn't change, but I think the moment being more magnified with runners in scoring position, guys get away from their approach a little bit and try to do too much.

"The pitch selection suffers a little bit. That's something, as a young club, we've got to continue to stress and get better at."

Overall, Barnett has been pleased with the offense. The Astros entered Tuesday ranked third in the NL in both runs scored (76) and on-base percentage (.332), and were sixth in batting average (.255).

"We've had a couple of really big games, scoring 12 runs and 11 runs, and we've got to find a way to get more consistent night in and night out, and that comes more into having a solid approach and not worrying about the situation," Barnett said. "You have to stay with your strengths and get a good pitch to hit in those situations. I'm very pleased with where we're at, but we've got a lot of learning to do."

Astros not happy about home-plate collision

MILWAUKEE -- Jason Castro was out of the starting lineup Tuesday, one day after he was flattened in a home-plate collision with the Brewers' Mat Gamel.

Astros manager Brad Mills said Castro wasn't scheduled to play anyway and, other than a sore neck, Castro said he was feeling fine.

Mills, who said Gamel would have had a good shot at being safe had he slid, didn't think Gamel had to bowl over Castro, who was knocked down and hit the back of his head on the ground while holding onto the ball for a double play to end the sixth inning. He stayed in the game.

"My first thought was he must have the plate blocked, and then I found out he didn't have the plate blocked and I said, 'C'mon, man,'" Mills said. "It was a situation [where] he was trying to knock the ball loose, but I thought Jason did a great job."

Veteran catcher Chris Snyder said it's important for catchers to expose the plate to the runner to avoid violent collisions like the one that occurred Monday.

"At this level, more times than not, you see guys that know what they're doing, and the catcher is going to give them the plate," Snyder said. "You see what's happened over the year with guys getting concussions on both sides of it, and what happened to [San Francisco's Buster] Posey last year. It's a reaction."

Snyder said collisions are a lot more common in the Minor Leagues, where young players are for the first time able to collide with the catcher in an effort to knock the ball loose.

"I got lit up quite a bit in the Minor Leagues, because there, you have kids just out of high school and college and there have been rules against it and they're just excited to be able to finally do it, and they don't know how to do it," he said.

When asked specifically about Gamel's leveling of Castro, Snyder thought it was unnecessary.

"I didn't like it," he said. "[Gamel] had the plate. It's a 6-2 ballgame. I didn't like it."

Johnson focusing on better pitch selection

MILWAUKEE -- Chris Johnson, who wasn't in the Astros' lineup at third base on Tuesday against the Brewers, had a long talk with hitting coach Mike Barnett about pitch selection and making adjustments.

Johnson is hitting .273, but he has struck out 20 times in 66 at-bats.

"When they've thrown the ball over the plate, he's put pretty good swings on it," Barnett said. "There really isn't anything mechanically wrong in his swing. He had a great Spring Training and swung the bat very well, and that's a credit to his swing. In Spring Training, pitchers are trying to get ready and they're going to throw more strikes."

What Johnson is dealing with now is a lack of good pitches to hit, as clubs who have noticed he'll chase pitches out of the zone have quit throwing him strikes for the most part.

"When I do get a pitch to it, I hit it pretty good," Johnson said. "I got here early [Tuesday], and that's something I'm going to try to focus on is pitch selection. I'm going to get better with it."

Johnson has been going to the bullpen to track pitches when the starters have been throwing on the side. He's also gone down in the cage and tracked pitches off a pitching machine that throws breaking balls.

"Pitch selection is huge at this level," Barnett said. "If they know you're going to chase, they're not going to give you anything to hit. He's aware of it, and we've talked about it at length. He's bound and determined to make the adjustments."

Worth noting

• Bud Norris tied a Major League record by striking out four batters in the third inning of Tuesday's game against the Brewers. Norris fanned Travis Ishikawa leading off the frame, but a passed ball allowed Ishikawa to advance to first. Norris then proceed to record the final three outs of the inning via the K.

Brewers starter Yovani Gallardo was the last pitcher to accomplish the feat, on Sept. 17, 2011.