"I've seen him throw live twice and his breaking ball is a lot better than our reports were," D-backs GM Kevin Towers said. "I knew he had a good change, live arm, good fastball, but I've seen a better breaking ball. It's a little bit of a slurve, but he looks to command it fairly well. Deception with his delivery, a lot of arms and legs -- I don't think right-handed hitters will be very comfortable in there facing him."
Peralta needs to improve his command, and he has an uphill battle to win a spot on the pitching staff. The D-backs' rotation is virtually set with the fifth spot to come down to Tyler Skaggs, Patrick Corbin and Randall Delgado.
The bullpen appears set with J.J. Putz, David Hernandez, Heath Bell, Brad Ziegler, Matt Reynolds, Tony Sipp and Josh Collmenter.
The D-backs paid the Cubs $50,000 to select Peralta and he must be kept in the big leagues for the entire 2013 season or be offered back to the Cubs for $25,000. It is also possible that the D-backs could wind up working out a trade.
"It's the kind of arm you'd like to keep in your system," Towers said.
D-backs manager Kirk Gibson will keep a close eye on Peralta over the next five weeks.
"He's overpowering," Gibson said. "Interesting guy to watch throw this spring, for sure. Just from watching him, it looks like he's got to command the zone more. He's got electric stuff."