HOUSTON -- Manager Dusty Baker said closer Aroldis Chapman is available to pitch on Sunday after pitching in the first two games of the series against the Astros.

Monday's off-day eases Baker's concern about his reliever, who hasn't given up an earned run in 23 appearances. But Baker will still make sure Chapman feels ready before calling him out of the bullpen.

"We just got to talk to him, see how he feels," Baker said. "If he has anything, if he feels anything, we tell him to just tell us the truth."

If this were August or September, Baker might be more aggressive with sending Chapman to the mound on the third consecutive day. Chapman has pitched three consecutive days only once in his career: from Sept. 9-11, 2010.

"Like I've said many times, it's not hero time," Baker said.

Chapman has struck out six batters in his two innings during the series. He hasn't given up any hits, but walked Chris Johnson on Saturday.

Frustration mounts for Reds' Costanzo

HOUSTON -- Mike Costanzo, mired in a 0-for-10 slump since picking up his first Major League hit on May 19, said Sunday that he's a little frustrated that the hits aren't coming.

On Saturday, Costanzo pinch-hit in the eighth inning and drove a ball deep to center field at Minute Maid Park. The Astros' Jordan Schafer caught the ball at full stride heading up the quirky hill in front of the center-field wall.

In many ballparks, it would've been a homer. In Minute Maid, it was an out.

"You really can't dwell on it, you just come back the next day and work hard and try to get it again," Costanzo said.

Manager Dusty Baker said he has sensed some frustration from Costanzo, but that he needs to call upon his success at the plate in the Minor Leagues, where Costanzo played for more than six years.

"If you're 1-for-whatever it is, you're going to be frustrated," Baker said. "He's doing a very tough thing and a very tough job, but that's his job right now. He's just got to figure out a way to be more productive in his job, and when he's not, don't go crazy about that one at-bat."

In Baker's eyes, the best pinch-hitters are veteran players with some history of success as a starter.

"Half this game is thinking that you can do it," Baker said.

Costanzo has yet to get a hit in a pinch-hitting role. His only hit in 17 at-bats came in his first start. For now, he'll just keep on working and waiting for his call to duty, looking for a hit that might get him on track.

"You get one cheap hit, and all of a sudden, you have 10 good ones in a row," Costanzo said. "When it rains, it pours in this game. What are you going to do?"

Worth noting

• The Reds are 8-0 in Sunday games this season and 13-4 in series finales.

• Since April 19, the Reds have been 2 1/2 games better than any other team in baseball, going 26-14 over that span. The Red Sox, Marlins, Dodgers and Rays are all 24-17 since April 19.