DENVER -- Relief pitcher David Carpenter, who rejoined the Astros on Monday after spending 10 days at Triple-A Oklahoma City, said he gained better command of his fastball while working with RedHawks pitching coach Burt Hooton, in addition to Astros pitching coach Doug Brocail.

Carpenter was sent down on May 25 after going 0-2 with a 4.02 ERA in 14 games for the Astros. He pitched in four games for the RedHawks, allowing two earned runs in 5 2/3 innings. More importantly, he ironed out some issues.

"Burt tweaked a couple of things in my delivery that I had talked to Brocail about prior to going down, and Burt kind of reaffirmed it," Carpenter said. "It was just a couple of things I needed to change, small tweaks. I really felt that it helped out getting on top of the ball more and being able to throw down in the zone a little better and spotting stuff where I wanted to."

While in Oklahoma City, Carpenter said he got back to being relaxed, instead of trying to force things with his mechanics and throwing the ball as hard as he can.

"I'm worrying about putting the ball where I want to instead of trying to throw it as hard as I can, so that was just one of the main things I worked on with Burt," Carpenter said. "I just had to get back to that consistent, relaxed attack."

Carpenter hadn't pitched since May 24 entering play on Wednesday.

Richard to be inducted to Walk of Fame

DENVER -- Former All-Star pitcher J.R. Richard will be inducted into the Astros Walk of Fame at 3 p.m. on Friday. The Walk of Fame, which was unveiled this year, is situated along Texas Avenue outside of Minute Maid Park.

During his 10-year Astros career, Richard was one of the most feared pitchers in the game, setting several strikeout records while compiling a 107-71 record with a 3.15 ERA. Richard ranks near the top in most pitching categories on the Astros all-time lists.

Richard is scheduled to sign autographs on the main concourse from 6-6:30 p.m. prior to Friday night's game against the Reds. A limited amount of autograph vouchers ($25) are currently available for purchase at www.astros.com/flashback. One voucher per customer is allowed. One voucher is good for one autograph.

Richard will throw out the ceremonial first pitch prior to Friday's game, in which the Astros will wear the popular rainbow jerseys from the 1970s. The Astros are wearing a jersey from the team's past during Friday home games this year as part of the team's 50th anniversary.

Worth noting

• Jarred Cosart, the Astros' top pitching prospect, was skipped in the rotation Wednesday for Double-A Corpus Christi's game at Arkansas for "failure to conform to club policy," director of player development Fred Nelson said. Cosart is scheduled to pitch again Sunday in Springfield.

• Jordan Lyles could be called up to start Sunday's game against the Reds in Houston. Lyles started the second game of Monday's doubleheader and was sent back down to Triple-A, but because he was the 26th man on the roster, the 10-day minimum requirement to stay in the Minor Leagues has been waived.