"There's separation from guys that you think have a chance to be 'Yo' [Yovani Gallardo] and [CC] Sabathia and [Zack] Greinke, and other guys are just going to be good Major League pitchers," Roenicke said. "But Peralta has enough special stuff that he has a chance to be one of those [top-tier] guys."
Peralta, vying for a spot in Milwaukee's rotation, has yet to see hitters in camp because the Brewers backed off slightly after he reported some stiffness following his first Arizona bullpen session. Peralta is not pitching in the World Baseball Classic, so there is no need to rush him along, Roenicke said.
Peralta was 7-11 with a 4.66 ERA last season at Triple-A Nashville, then was 2-1 with a 2.25 ERA in five September starts with the Brewers. He is MLB.com's top Brewers prospect.
Eventually, he is expected to join the race for three rotation spots behind Gallardo and Marco Estrada. Besides Peralta, the competitors include left-hander Chris Narveson and right-handers Mike Fiers and Mark Rogers.
Roenicke extolled the virtues of that group, disputing the notion that it amounts to Gallardo and "four other guys."
"I don't view it that way," Roenicke said. "If we thought that was the case, I think we would have gone out and got a veteran. Maybe not a great veteran, but a veteran we knew could come in and be a third or fourth pitcher. We have some guys who we think can be better than mediocre."
The Brewers did make a strong play for free agent Ryan Dempster, but he picked Boston instead. General manager Doug Melvin viewed Dempster as a particularly perfect fit, given his past success at Miller Park and his high character, and when Dempster spurned their offer, the Brewers decided to stick with their internal options.
Roenicke extolled Fiers' and Estrada's strikeout rates last season, and Rogers' and Peralta's pure stuff.
"Peralta is more an up top, power, moving ball that's coming down in the zone, with a tight, nice slider that's going to be a 'punchout' slider [type of pitcher]," Roenicke said. "I know he didn't punch out a lot of guys in Triple-A last year, but when he got to us and he commands both of those, he's going to be a punch-out pitcher.
"Rogers is more an explosive, up in the zone, 'I'm going to throw it up here and you can't catch up' [type pitcher]. That's a completely different pitcher, even though velocities are the same. Peralta is going to be a better pitcher when he's down in the zone; Rogers might be a better pitcher when he's up in the zone and up above the zone."