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3/9/2014 8:11 P.M. ET

Bradley to start exhibition game vs. Team Australia

SCOTTSDALE, Ariz. -- Top prospect Archie Bradley will get the start against Team Australia in an exhibition game March 21 in Sydney.

"That's very exciting," Bradley said. "I'm still taking it in myself. I'm very pleased to be going; I think it's going to be a fun experience. Again, it's another learning experience, it's going to be my first road trip with these guys, and I'm going to just continue to learn from it, learn how to travel."

While that effectively means Bradley will not pitch in the two-game regular season series with the Dodgers on March 22-23, Arizona manager Kirk Gibson said the move means that Bradley is still in the mix to be in the rotation when the D-backs re-start the regular season March 31 against the Giants.

"I think it's a great experience for him," Gibson said of Bradley getting the exhibition start. "Kind of give him the exposure. It's important for him to get that, to get into more elevated, high-leverage situations that he's got to deal with things and keep control over."

Bradley, 21, has been impressive in a pair of Cactus League starts tossing 6 1/3 scoreless innings.

Ranked as the top pitching prospect in the Majors by MLB.com, Bradley was expected to compete for the No. 5 spot in the rotation when camp opened. However, the D-backs signed free agent Bronson Arroyo a few days after camp started, which seemed to end Bradley's chances.

Arroyo, though, has been sidelined for a week with a bulging disc in his back.

"He's still in the mix," Gibson said of Bradley. "We're kind of waiting to see where Arroyo works out, see how the whole dynamic of the starting staff will work out."

After not feeling great while playing long toss Saturday, Arroyo said that his back was better Sunday and he hoped to throw a bullpen session Wednesday and then be able to pitch in a game on March 14.

"I'll have three starts and then be ready for the season," Arroyo said. "I would have loved to have only missed one, but I can make up the difference maybe in some extra days of long toss and hopefully feel strong."

Any setback in that timetable could open the door for Bradley, Bo Schultz, or Randall Delgado to make the rotation.

Gibson still has faith in struggling Putz

SCOTTSDALE, Ariz. -- D-backs reliever J.J. Putz's numbers have not been impressive this spring, but manager Kirk Gibson has not lost faith in the right-hander.

Putz, who was expected to battle Addison Reed for the closer's role, has a 6.75 ERA after four spring games.

"He's working on a lot of stuff," Gibson said. "He's trying to make some changes to some of the things he's doing. His mechanics are a little different. He's trying to use his two-seamer more. It's coming along pretty good. The four-seamer, he seems to have a little trouble right now getting the ball down. His velocity probably isn't where he wants it, but it's been there before. The thing about J.J. is he's pitched a lot games, he's been through a lot of Spring Trainings, he's saved a lot of games, and I think that when the season starts, it'll be a whole different game for him."

Putz finished 2013 strong after struggling with some injuries early in the year that set him back and bumped him out of the closer's role.

Last year Putz had a 2.36 ERA in 40 games after saving 45 games for the D-backs in 2011 and 32 in 2012.

"We've probably pushed him harder this spring," Gibson said. "Thrown more at him, but I think when the season starts he's going to be ready and he's going to be just fine."

After latest moves, D-backs roster down to 40

SCOTTSDALE, Ariz. -- The D-backs made 13 roster moves Sunday pairing the number of players in camp down to 40.

Pitchers Eury De La Rosa and Zeke Spruill along with outfielders Ender Inciarte and Alfredo Marte were optioned to Triple-A Reno.

There were nine non-roster players reassigned to Minor League camp. This included pitchers Jake Barrett, Mike Bolsinger, Adam Russell and Matt Stites; infielders Nick Ahmed, Nick Evans and Jake Lamb; catcher Bobby Wilson and outfielder Danny Dorn.

The D-backs will need to pair their roster to 28 before leaving for Australia next Sunday.

Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.