HOUSTON -- Infielder Tyler Greene, who was acquired from the Cardinals in a trade on Thursday, joined his new team Friday afternoon, though he wasn't in the starting lineup. Greene found some friends in bench coach Joe Pettini, formerly of the Cardinals, and former Minor League teammate Chuckie Fick.

"There's a lot of familiar faces in the clubhouse, which is nice," Greene said.

Greene will split playing time at shortstop with Marwin Gonzalez, with Gonzalez getting most of the starts against right-handed hitters. A switch-hitter, Gonzalez was hitting .292 vs. right-handers entering Friday and .119 against lefties. Greene is hitting .245 against lefties.

"I'm excited about this opportunity to join a new ballclub, a new franchise," he said. "I'm just looking forward to coming out here and helping to contribute in any way I can with this team."

Greene, who won a World Series last year with Cardinals, joins an organization that's rebuilding, and he wants to be part of the trend upwards.

"I'm going to bring the work ethic, all the information I learned from the Cardinals organization and try to help out any way I can, and hopefully that's for the present and the future," he said.

Astros promote outfielder F. Martinez from Triple-A

CIN@HOU: Martinez's two-run double reviewed, upheld

HOUSTON -- The Astros on Friday called up outfielder Fernando Martinez from Triple-A Oklahoma City, where he was hitting .314 with 13 homers, 62 RBIs and a .367 on-base percentage. He will join the team in time for the series opener against the Brewers and will wear No. 21.

The move gets the Astros' active roster back to 25, with infielder Tyler Greene also joining the club Friday after being acquired in a deal with the Cardinals on Thursday. The Astros optioned infielder Matt Downs and outfielder J.D. Martinez to Triple-A following Thursday's game.

Fernando Martinez was with the Astros earlier this season and hit just .067 in four games before being put on the disabled list after suffering a concussion. He did his rehab in Triple-A and remained there when he was activated from the DL.

The Astros claimed him off waivers from the Mets in January.

Considered one of baseball's top prospects from 2006-10, Martinez, 23, was billed as a power-hitting outfielder who was expected to be a cornerstone of the Mets' lineup throughout this decade. But multiple injuries and an arthritic right knee prevented Martinez from appearing in more than 82 games in any of the past three seasons.

Martinez spent the majority of the 2011 season at Triple-A Buffalo, but he did have a brief stint with the Mets. In 63 games with Buffalo, he hit .260 with eight home runs and 30 RBIs. He also had brief stints with the Mets during the '09 and '10 seasons, appearing in a combined 36 games in that span.

Astros legend Bagwell throws out first pitch

HOUSTON -- The loudest cheers Friday night came prior to the game when Astros legend Jeff Bagwell threw out the ceremonial first pitch during "Flashback Friday." In celebration of their 50th anniversary, the Astros have a different former player throw out the first pitch prior to each Friday home game.

Bagwell tossed the pitch left-handed to Astros infielder Brett Wallace because of the degenerative right shoulder condition that forced him to retire after the 2005 season.

"Well, I can't throw right-handed, so I had to throw left-handed," Bagwell said. "It was fun. I wish we had more people here, and it's not for me, for the team. Times are tough right now, but we're going in the right direction. It's all good."

Bagwell has kept a low profile since deciding not to return as the team's hitting coach following the 2010 season, a job he held for the second half of the year. He's still listed in the team's media guide as a special assistant to the general manager.

When asked what role he'll play in the future, he was non-committal.

"I just want to wait and see what's going on and see what direction we're going in, and we'll [decide] at some point," he said.

Bagwell, who will be on the Hall of Fame ballot for a third time this offseason, was charged with an error when he threw the 24-karat gold leather covered ball with the Astros' 50th anniversary logo into the stands as he walked back to the dugout.

Paredes likely to be called up in September

HOUSTON -- Those clamoring to see Jimmy Paredes back in an Astros uniform might not have to wait much longer.

Astros general manager Jeff Luhnow said Friday that Paredes, who's playing center field for the RedHawks, will join the big league club when rosters are expanded in September, assuming all goes well the next few weeks. Paredes entered Friday hitting .322 with 12 homers, 53 RBIs and 31 steals.

Luhnow said the Astros chose to call up Fernando Martinez instead of Paredes on Friday partly because Paredes hasn't had much time in the outfield. He has played six games in the outfield, mostly in center, after playing most of the season at second base.

"We wanted Paredes to get his reps out in center field," said Luhnow, who pointed out the Triple-A center field job became open when Brandon Barnes was promoted to Houston earlier this week. "He's going to play there the rest of the month. Assuming that goes well, we're going to see him here in September. It's hard to learn a new position in the big leagues. I've seen that happen before, and it can be a big challenge. We don't want to put that on him right now."

Paredes, a switch-hitter acquired from the Yankees in the Lance Berkman trade two years ago, had played second, third and shortstop before the Astros opted to move him to the outfield recently. He started at third base for the Astros the final two months of last year.

"He's very capable of playing center field and he has all the tools in the world," Luhnow said. "Ultimately, that may end up being his best position given his speed, his ability to throw and that stuff. Clearly, he can hit and he's proven that. I'm excited. We'll see him at some point."

Another one of the Astros' top prospects, second baseman Delino DeShields Jr., was promoted to high Class A Lancaster on Friday after hitting .298 with 10 homers, 52 RBIs, a .401 on-base percentage and 83 stolen bases at Class A Lexington.

"He's absolutely earned it," Luhnow said. "You could argue his promotion was overdue at this point, and I'm excited to see what he can do at the next level. He's definitely put himself on the map as a player we want to see here in the next couple of years. I can't wait."

Outfielders discuss possibility of removing Tal's Hill

HOUSTON -- Astros owner Jim Crane has said on a pair of occasions the club is considering getting rid of Tal's Hill, the incline that's in play in straightaway center field in Minute Maid Park. That could cost the Astros a little bit of a home-field advantage.

Center fielder Justin Maxwell made a diving catch on the hill Thursday, a play which he said he learned to make after chasing a Garrett Jones ball to the hill earlier this year and having his legs unexpectedly cut out from under him.

"[Thursday], as I felt myself on the warning track right before I was going to catch the ball, I jumped just so I wouldn't trip because I knew if I was going to run full speed I was going to fall like last time," he said. "But I'm glad I made the play."

Fellow center fielder Jordan Schafer said earlier this year he hoped the hill would be removed because of the risk of an injury, but Maxwell -- who has ample power -- is torn.

"It's good for our pitchers, just because that part of the ballpark is so huge," he said. "And from a defensive outfield standpoint, I don't have to worry about the wall and I can run for a day. I like it for defense, but as a hitter, if they want to get rid of it, sure."

Worth noting

-- Catcher Jason Castro, who's been on the disabled list since July 8 with a right knee injury, is scheduled to rejoin the Astros, perhaps as early as Sunday's game against Milwaukee. Castro was scheduled to catch nine innings Friday and Saturday for Triple-A Oklahoma City.