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8/31/2013 2:26 A.M. ET

Ludwick back at cleanup spot for Reds

DENVER -- Ryan Ludwick returned to the cleanup slot in the Reds' lineup for Friday's series opener in Colorado. It was his first time batting fourth since Opening Day.

Ludwick tore the labrum in his right shoulder sliding into third in the season's inaugural tilt, and he was on the disabled list until Aug. 12, recovering from surgery.

The Reds are 10-7 since his return, and he hit safely in seven of his last 10 games entering Friday for a .303 (10-for-33) average. Ludwick was a career .377 (26-for-69) hitter at Coors Field, the site of Friday's series opener, with eight homers and 22 RBIs.

He was 1-for-4 with a double and an RBI in Wednesday's 10-0 rout of the Cardinals, a game in which the Reds tallied 13 hits.

"We were excited before, we were just getting our butts kicked," manager Dusty Baker said of the attitude shift in the dugout Wednesday after losing the first two games of the series to the first-place Cardinals. "We know what's at stake; we know what's at hand. It's easy to get excited when you're beating somebody."

Expected callups include top prospect Hamilton

DENVER -- With the Reds maintaining their grip on a Wild Card berth and staying within 3 ½ games of first place in the division despite losing their series opener in Colorado on Friday, they are poised for a dramatic influx of talent when the rosters expand Sunday.

Heading the list of potential callups is shortstop-turned-center fielder Billy Hamilton, rated the Reds' No. 1 prospect and No. 17 in Major League Baseball by MLB.com, largely as a result of his untouchable speed.

Hamilton set a professional baseball record in 2012, stealing 155 bases in 192 attempts over 132 games split between the Reds' Class A and Double-A affiliates. To steal those bases, he had to get on base, and his 2012 successes at the plate were impressive. He hit .311 with a .410 on-base percentage, and though his numbers have fallen off in a full season at Triple-A Louisville, he still leads the International League with 75 steals in 90 attempts, 33 more steals than the next closest speed merchant.

Hamilton is one of six players poised to join the Reds when rosters expand Sunday, though he will most likely make his much-anticipated big league debut when the Reds return home for a 10-game homestand Monday.

The Reds already made one key move in advance of Saturday's Waiver Trade Deadline, when rookie right-hander Nick Christiani was optioned to Triple-A Louisville on Friday, bringing veteran southpaw Zach Duke to the Reds in time to be eligible for a spot on the postseason roster. Duke threw 1 2/3 scoreless innings in Friday's 9-6 loss to the Rockies.

Christiani pitched well in his Major League debut, pitching 1 1/3 scoreless innings to finish last Friday's 6-4 loss to the Brewers. He walked one, struck out one and allowed no hits. It was his only appearance with the Reds, but he will be back soon.

"He's going to go and pitch, and then come join us at home," manager Dusty Baker said.

The Reds anticipate calling up three players from Louisville for Sunday's series finale with the Rockies, including infielder Henry Rodriguez, outfielder Derrick Robinson and right-hander Curtis Partch.

They anticipate three more moves when they return home Monday to face the Cardinals. The Reds expect to purchase the contract of Hamilton from Louisville and to recall infielder Neftali Soto. Catcher Corky Miller should also return from his stint on the 15-day disabled list. He is recovering from a right quad contusion following a home-plate collision Aug. 7 against Oakland and was 1-for-2 as a designated hitter in a rehab start at Columbus on Thursday.

Hamilton has played his entire career at short, but the Reds feel his speed is better suited to center field, and the 22-year-old from Mississippi has made a comfortable transition, eager to find the fastest path to the Majors.

After he led five different levels of Minor Leagues in steals over four seasons, it should be no surprise that Hamilton has found a fast track to contribute to the Reds pennant race.

Seeking a lefty for 'pen, Reds call up Duke

DENVER -- With an eye to October, the Reds purchased the Triple-A contract of left-hander Zach Duke to bolster the bullpen while sending right-handed rookie Nick Christiani back to Louisville, shortly ahead of Saturday's Waiver Trade Deadline. To make room on the 40-man roster for Duke, the Reds designated right-handed pitcher Justin Freeman for assignment.

"I'm very happy, very excited," Duke said of the move, returning to the Majors after being released by Washington in June and regaining his game in Louisville. "I'm ready to help this team win games."

The 30-year-old Duke struggled in Washington in the first few months of the season, posting an 8.71 ERA in 12 games and 20 2/3 innings before his June 10 release. He was a starter for the first six years of his big league career in Pittsburgh, then was used primarily in relief in Arizona in 2011 and with Washington in 2012, when he posted a 1.32 ERA in eight games before faltering this year.

"I didn't perform very well with the Nationals," Duke said. "I am certainly [throwing] better than earlier in the year. I got more regular work with the role I was in there in Louisville. I got in a good groove. I'm commanding the ball well and mixing it up well."

Though rosters expand Sunday, the move before the end of August makes Duke eligible for the playoff roster and gives the Reds a more balanced bullpen. The Reds now have three active left-handers: Duke, Manny Parra and closer Aroldis Chapman.

"I've never been opposed to having three lefties," manager Dusty Baker said. "The Pirates always had three lefties back in the day when Jim Leyland was there.

"It's hard with one lefty, because you have to wait until the opportune time. If you have two, you can throw one in the sixth and one in the eighth. There was a lot of pressure on Manny [Parra]. There was pressure on us about when to put Manny in the game. The game could have been lost in the sixth, or it could have been lost in the eighth. Duke will probably be the secondary lefty, and Manny will be the primary lefty. That's the plan."

Duke thrived in Triple-A, going 2-0 with a 1.30 ERA in 26 games spanning 27 2/3 innings. He gave up only five walks while striking out 34.

"I'm just trying to be crafty," Duke said of the adjustments he made since coming from Washington. "Really the whole thing is just executing. The hitter will tell you what pitch you should throw, and then it's a matter of execution. I feel like I'm executing right now."

Owen Perkins is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.