HOUSTON -- The Astros haven't completed the long climb back to .500 following their abysmal opening month, but on the heels of their first sweep in St. Louis since May 11-13, 2010, momentum is building.

In the three-plus weeks since they fell a season-worst 11 games below .500 on May 22, the Astros have won 15 of 22 games.

They open a brief but crucial six-game homestand against the Cincinnati Reds on Friday night, their first meeting with their former National League Central rivals since absorbing a three-game sweep at Minute Maid Park Sept. 16-18, 2013, the Astros' first season in the American League. The Astros are 20-44 against the Reds since last winning a season series in 2008.

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Their two victories over the Cardinals enabled the Astros to salvage a 4-5 road trip through Texas, Tampa Bay and St. Louis, one that began with three losses during a four-game series against the Rangers. With just six of their final 22 games before the All-Star Game break on the road and only six games against teams currently sporting winning records (the Royals and Mariners), the Astros (32-35) are positioned to play their way back into the postseason picture.

"Obviously, we've had a couple of series in there that we've had some close losses, but we can hang with anybody and we have a good team," Astros manager A.J. Hinch said to MLB.com. "We've got to keep battling."

Astros right-hander Lance McCullers (3-2, 4.54 ERA) makes his fourth career interleague start and will be opposed by Reds rookie left-hander John Lamb (1-4, 5.14 ERA), who has allowed multiple home runs in three of his last five starts but is 1-1 with a 2.95 ERA this month.

The Reds (26-41), just 2-8 in interleague play, are 5-6 since a season-best four-game winning streak June 1-4 yet joined the Marlins as the only team to drop consecutive games to the Braves at Turner Field with their 7-2 loss Thursday.

With right-hander Raisel Iglesias already on the 15-day disabled list with a sore right shoulder, the Reds lost righty A.J. Morris to the DL with a right shoulder strain Thursday. Southpaw Cody Reed will be promoted from Triple A Louisville to make his major league debut Saturday.

Reed, the Reds' No. 3 prospect according to MLB.com, was acquired from the Royals in the Johnny Cueto trade last July. He is 6-3 with a 3.20 ERA in 11 starts with 63 strikeouts against 17 walks in 64 2/3 innings.

"It's just another piece," Reds manager Bryan Price said of Reed to MLB.com. "It's another piece of putting this together, where we have some consistency and some young pieces that get a chance to grow."

Price and the Reds need to remain patient with so many youngsters in their rotation. One of their few veteran starters, right-hander Dan Straily, lasted 4 2/3 innings in the finale against the Braves, leaving left-hander Brandon Finnegan as the lone starter to pitch through the fifth inning over the Reds' last five games.

"I've got some guys down there (in the bullpen) who are willing to take the ball when they're out of gas and they'll continue to come out and pitch," Price told MLB.com. "But that's just not the way you compete. You don't want to get into situations where you're finishing a game with your backend bullpen pieces that are already tired, just simply as to finish a game."