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7/19/2013 10:33 P.M. ET

Collmenter's role in bullpen could expand

SAN FRANCISCO -- Josh Collmenter has pitched admirably in his role of long reliever this season. So much so that the club is considering using him later in games.

The D-backs have had issues holding leads and were tied with the Cubs for the most blown saves (19) in baseball entering Friday. Collmenter has been a consistent and solid presence in the bullpen, sporting a 2.55 ERA in 26 outings.

When asked whether Collmenter's success could lead to a more prominent role, manager Kirk Gibson said it might but that the team does not have another clear long-relief option.

"If you pitch him too much [as a setup man], then who's the long guy?" Gibson said.

Gibson presented the possibility that Collmenter could throw multiple innings as a setup man before handing the ball over to closer Heath Bell.

"We'll see where we're at in the game," Gibson said. "It's possible. He could pitch [innings] six, seven and eight.

"We'll come back and see how everybody's throwing and go from there."

McCarthy set for Triple-A rehab assignment

SAN FRANCISCO -- Brandon McCarthy took the next step toward returning to the D-backs on Friday when he threw a bullpen session at the club's Spring Training complex in Scottsdale, Ariz. He is scheduled to begin his rehab assignment with Triple-A Reno on Sunday.

D-backs manager Kirk Gibson said McCarthy will throw in two games while on his rehab assignment, if all goes as planned.

"He's gotten real good reports," Gibson said. "I haven't been able to watch him."

McCarthy, who threw a simulated game Sunday, was placed on the disabled list with shoulder inflammation June 1. It marked his second injury stint due to a shoulder issue in as many seasons.

He is 2-4 with a 5.00 ERA in 11 starts with the D-backs this season.

D-backs mindful of Corbin's innings count

SAN FRANCISCO -- All-Star Patrick Corbin turned 24 years old on Friday, but at this point the talented left-hander might be counting innings more than candles.

Corbin's inning of relief in Tuesday's All-Star Game will be his only outing in a span of 11 days between starts. Manager Kirk Gibson reiterated Friday that the club will not start Corbin until Tuesday in an effort to monitor his innings.

"He's been our savior," Gibson said. "Without Patrick, we wouldn't be in good shape at all."

Corbin has been the ace of the D-backs' rotation with an 11-1 record and 2.35 ERA in 19 starts. He has tossed 130 1/3 innings and is on pace to shatter his career high of 186 1/3 from last year between Arizona and the Minor Leagues.

"We've got to take care of him," Gibson said. "We're erring conservatively. You also worry about giving him too much time off."

Cahill makes progress in second throwing session

SAN FRANCISCO -- D-backs starter Trevor Cahill completed his second throwing session earlier this week, and manager Kirk Gibson said Friday he did not know when the right-hander would throw next.

In the latest outing, Cahill threw 40 pitches after tossing 20 in his first session.

"He threw the ball well, working on some mechanics," Gibson said. "He threw the ball much better than he did the first time."

Gibson added that Cahill is "way behind [Brandon] McCarthy," who is set to begin a rehab assignment with Triple-A Reno on Sunday.

Cahill has been on the disabled list since July 1 with a right hip contusion and was slowed by shoulder soreness two weeks ago, although the shoulder issue has subsided.

Last week, D-backs general manager Kevin Towers said it looked like Cahill might not be able to return until early August.

This has been Cahill's toughest season in his five-year big league career. Before the injury, he was 3-10 with a 4.66 ERA in 17 starts.

Snake bites

• Arizona won consecutive road games entering the All-Star break but was just 3-10 in its past 13 away from Chase Field.

• First baseman Paul Goldschmidt entered the series with a Major League-best eight home runs and 28 RBIs against San Francisco since 2011. He also leads baseball with five home runs and 17 RBIs at AT&T Park during that span, along with a .349 average.

Andrew Owens is an associate reporter for MLB.com. Follow him on Twitter @OwensAndrew. This story was not subject to the approval of Major League Baseball or its clubs.