HOUSTON -- With the way Reds reliever Aroldis Chapman has pitched this season, his exact role out of the bullpen hasn't really mattered.

But since being named the closer on May 20, Chapman has been especially dominant, striking out nine in 5 2/3 innings of work and not giving up a hit.

"He just had to graduate mentally and psychologically into that role," manager Dusty Baker said.

On Friday against the Astros, Chapman picked up a save and finished off three strikeouts with fastballs, two of which registered a 100-mph reading on the stadium gun. He hadn't struck out the side in a one-inning appearance this season.

"If he can get by with fastballs -- I tell the guys -- why throw something else?" Baker said.

Baker will definitely use his relief ace whenever he needs him, but he will also monitor Chapman's strength and be sure not to use him too often.

"He's not the same after a couple consecutive days," Baker said.

Chapman has pitched in back-to-back games three times this season, all coming since May 16. As the closer, Chapman has pitched in back-to-back games once -- on May 22-23.

He's pitched in three consecutive games only once in his career: from Sept. 9-11 in 2010. Baker said he couldn't foresee using Chapman in three consecutive games.

"Unless we just have to," Baker said.

Bruce sits for matchup with Astros lefty Wandy

HOUSTON -- Manager Dusty Baker took Jay Bruce out of the Reds' lineup for Saturday's game against the Astros, citing the right fielder's lack of success against starter Wandy Rodriguez.

In his career, Bruce is 2-for-29 against Rodriguez, striking out 15 times and never drawing a walk. Bruce also doesn't have an extra-base hit off the Astros lefty.

Baker said it was tough to sit Bruce, especially considering that he has family and friends in town for the game. Bruce is originally from Beaumont, which is 83 miles from Houston.

"I don't like sitting him, but sometimes -- what is he, 2-for-30 with 15 strikeouts? -- it's not good numbers," Baker said.

Bruce didn't talk with Baker before finding out that he wasn't in the lineup. He was disappointed to not start but respected Baker's decision and opinion. Bruce is available for pinch-hitting duties.

"I feel like I'm someone that can contribute every day," Bruce said.

Chris Heisey took Bruce's place in right field and in the fifth spot in the lineup. Heisey is 3-for-9 off Rodriguez in his career, with a double and a homer.

On April 27, the Reds also faced Rodriguez and the Astros. Bruce batted seventh in the lineup, two spots behind his usual position. He went 1-for-3 against Rodriguez in that game, striking out twice.

Worth noting

• Manager Dusty Baker said third baseman Scott Rolen's status was the same as it was a few days ago as Rolen continues to rehab his injured left shoulder in Cincinnati.

"He's trying," Baker said. "He's working out, trying to get back on the field. I'm sure he has a ways to go."

Todd Frazier, who has been the major fill-in for Rolen at third, is batting .222 since Rolen went on the disabled list on May 12. He has four homers in those 18 games.

• First baseman Joey Votto continued his impressive run of success at Minute Maid Park on Friday, boosting his career average in Houston to .408 (51-for-125).

He singled in his first and second at-bats.

"When you're able to hit in a park, you don't ask why," Baker said. "When you're not hitting, you try to figure it out."

Votto currently has a 19-game hitting streak at Minute Maid. In that span, he is 37-for-79 (.468) with 12 doubles, two triples and four homers.