"He's got good stuff. He can get guys out -- lefties and righties," Arizona manager Kirk Gibson said. "A good changeup, he's got the stuff to get righties out as well. … It's good when you can leave the guy in there. You don't have to pull him out just because he can't get a right-handed guy out, so we're hoping he can do that."
Reliever Brad Ziegler added: "He's definitely qualified. He's had a good year in Triple-A. He's been up here before and got his feet wet and he knows what it takes to succeed here. We're guessing we can throw him in the same situations as we put Thatcher in and we're going to get the same results."
Walks hurt De La Rosa last season, as he issued 3.1 free passes per nine innings in the Majors. He has not shown much improvement in that area this season, as he has walked 4.6 batters per nine, down from his rate of 4.9 with the Aces in 2013.
"Thatcher used to walk a lot of guys, too," Gibson said. "[Bullpen coach Mel Stottlemyre] and [pitching coach Mike Harkey] did a good job with him. We're going to try to use him right. Put him in a situation where [De La Rosa] can throw the ball more consistently, throw it over the plate and get outs."
However, De La Rosa should fit right in to a D-backs bullpen that led the National League and ranked second in the Majors with 287 strikeouts entering Saturday. The 5-foot-9 De La Rosa has fanned 9.5 per nine innings in 332 career innings in the Minor Leagues.
"He's pretty nasty, especially [since] he's not very big," Ziegler said. "I think he catches a lot of hitters off guard with how good his stuff is."
Should he make an appearance during this weekend's series at Turner Field, De La Rosa likely has a good chance to build on his ratio of 9.8 strikeouts per nine in the Majors. Braves batters entered Saturday ranked fifth among all teams with 728 strikeouts.
"He's been up here before, he's got a little bit of experience," Gibson said. "He should get comfortable quickly. He should be more comfortable this time being up than he was in previous stints. He can do it."
Joe Morgan is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.