CHICAGO -- Cesar Valdez will be called up from Triple-A Reno and start in place of the injured Kris Benson on Monday in Houston.

Valdez was 1-1 with a 3.80 ERA in four starts for Reno this year with 25 strikeouts and five walks in 23 2/3 innings.

The 25-year-old got the nod over Kevin Mulvey, Billy Buckner and Bryan Augenstein.

"I think he's pitched the best," D-backs manager A.J. Hinch said. "He's had a good run of starts. He'll get his first taste of the big leagues and we'll give him the opportunity to stick."

Benson was forced to leave Wednesday's start in Denver due to a strained pectoral muscle. The team called up Mulvey on Thursday and used the starter out of the bullpen Friday against the Cubs.

Valdez was named the organization's Minor League Pitcher of the Year in 2008 when he had 13 wins between Class A Visalia and Double-A Mobile. Last season was a struggle for him at Reno, as he went 7-6 with a 4.78 ERA in 19 games [18 starts].

"He's a guy that needs to pound the strike zone and rely on his defense," Hinch said. "He lost a little bit of his aggressiveness last year and I don't know if it was because it was his first taste of Triple-A or what it was, but he lost a little of his edge and conviction. Something clicked for him in spring and it felt like the old Cesar Valdez was back."

Haren hitting his stride at plate

CHICAGO -- Dan Haren's prowess with the bat gives manager A.J. Hinch an added option off the bench on days he's not pitching.

But the D-backs manager is also cautious in how he uses his ace at the plate.

"There's always a risk," Hinch said. "He's still not as comfortable at the plate or on the bases as a position player."

Haren his 9-for-18 with a pair of doubles this year at the plate and got a hit in his lone pinch-hit appearance this year.

"I'm not trying to do too much," Haren said. "I'm not going up there trying to hit home runs."

When he is going to use Haren to pinch-hit, Hinch gives him plenty of notice so that he can make sure to get stretched and loose.

And just like with position players, the more success he has the more confident Haren feels.

"Not that I would say I expect to get a hit when I come to the plate, but I feel comfortable, I feel the game is not moving that fast," Haren said. "Sometimes you get up there and everything looks like it's moving so fast, but when things are going good everything slows down."

Tracy faces former teammates

CHICAGO -- Chad Tracy has not gotten many starts for the Cubs this year, but the former D-backs infielder made the most of his opportunity Sunday.

Tracy went 3-for-4 with a walk, three runs scored and an RBI against his former team, though he took no added satisfaction in doing so.

"I have a lot of friends over there and it's a good group, a bunch of good guys," Tracy said. "I consider them good friends and I wish them well now that they're out of here."

Tracy started in place of Aramis Ramirez at third. It was only his second start of the season and he said there was no added excitement in facing Arizona.

"For me, it was like playing a regular game," he said. "I didn't feel a whole lot of emotion at all. It was just playing baseball."

Tracy was originally drafted by the D-backs and played in the big leagues with them from 2004-09 before departing as a free agent.

Rosa aquired from Royals

CHICAGO -- The D-backs added to their Minor League bullpen depth Saturday night after acquiring right-hander Carlos Rosa from the Royals in exchange for Minor League shortstop Rey Navarro.

The Arizona bullpen has struggled mightily so far this season -- entering Sunday's game with the worst ERA in the National League.

"We're excited to get him because he's another guy that has some upside to potentially land in our bullpen," D-backs manager A.J. Hinch said. "We'll see what he looks like in Triple-A before we give him an opportunity up here if he earns it."

Rosa will report to Triple-A Reno. The 25-year-old was 2-1 with a 3.65 ERA in six games for Triple-A Omaha this season and made seven appearances for the Royals last year, posting a 3.38 ERA.

"We've seen him a couple of times in Spring Training," Hinch said. "He's a good arm. He's got a high arm slot with a good changeup, a good fastball that's low to mid 90s. He's going to go to Triple-A and compete to be a factor."

Navarro was drafted by the D-backs in the third round of the 2007 First-Year Player Draft and was hitting .241 for Class A Visalia.