PHOENIX -- Just how highly does Ron Roenicke regard right-hander Wily Peralta, the Brewers' consensus top prospect?

Milwaukee's manager offered a glimpse on Thursday morning.

"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."

Escobar's comeback begins with 'pen session

PHOENIX -- Right-hander Kelvim Escobar declared his 35-pitch bullpen session a success on Thursday, marking an unofficial launch to his first big league camp in three years.

The 36-year-old is bidding for a spot in the Brewers bullpen after beginning his comeback in the Venezuelan Winter League.

He threw all fastballs, "just to get a feeling again," Escobar said. "I was pitching in winter ball, so I knew I would feel fine."

Escobar will throw at least one more bullpen session before facing hitters. He's fine with his relatively slow progression.

"They said because the spring is going to be long, they don't want to rush me," he said. "They understand I was pitching in winter ball, but at the same time, they know I've been [away] for two years and it will take me a while to get back in baseball [shape]. No need to rush."

Escobar figured he would take a day or two off before taking the mound again.

"If he's fine, we may try to go a little harder with him," manager Ron Roenicke said. "It will be a conversation [pitching coach] Rick [Kranitz] will have with him. [Escobar] has been around long enough, he knows what he needs to do. And if he wants to do a little bit more, we'll try to do more."

Roenicke still planning for four-month Hart absence

PHOENIX -- Brewers manager Ron Roenicke was happy to hear that Corey Hart was so bullish about his return from knee surgery. Hart told a visiting ESPN reporter this week that he was aiming to be back at first base in the big leagues by April 20, which would beat the team's estimate by more than a month.

But Roenicke is still operating under the assumption that Hart will be out longer.

"It does make a difference, how you go about things mentally in coming back from injuries and rehabbing, and if he's positive, he's probably going to work harder," Roenicke said. "But the doctors tell us it's going to be four months [post-surgery] -- I'm going on that. If he comes back sooner than that, great. He says he's a fast healer, I hope he is. But I think, realistically, we're looking somewhere the later part of May."

Roenicke added again: "If he's back earlier, great."

Hart had surgery Jan. 25 to repair an imperfection in his knee joint and fix a small meniscal tear.

He has a follow-up MRI scheduled for March 8, at which point the timetable could become clearer. That timetable matters in this case because the Brewers already have lost their Plan B at first base, Mat Gamel, to a knee injury of his own, and will spend the first Cactus League games evaluating internal options like Bobby Crosby, Alex Gonzalez, Taylor Green and Hunter Morris. If Hart has any setbacks, the team may be more inclined to seek a regular first baseman from outside the organization.

Last call

• Center fielder Carlos Gomez and reliever Burke Badenhop have emerged as the Brewers' chief clubhouse characters, Roenicke said. He's happy to have some funny characters in camp.

"I like characters, maybe because I'm not [one]," Roenicke said with a smile. "I like to see personality."

• Roenicke has been polling veteran players about whether they want to play in Saturday's Cactus League opener against the A's, which comes earlier than usual because of the World Baseball Classic. Third baseman Aramis Ramirez, who is searching for ways to avoid his usual early-season slump, has already volunteered to play, Roenicke said.

• All of the regulars will play in Friday's intrasquad game at Maryvale Baseball Park because Roenicke wants to work on bunt defense in a game situation. That game is only scheduled to last about three innings, begin around noon MT and is open to fans.

• The Brewers said Lance Farbar and Krista Mulholland of Milwaukee, Laura Kachel of Waukesha, Wis., and Gregg Schmidt and Zach Zwadzich from Madison, Wis., were the first brave souls to set up camp at Miller Park on Thursday ahead of Saturday's "Arctic Tailgate." The event will mark the start of single-game ticket sales for 2013 Brewers home games.

The ticket windows will open at 9 a.m. CT on Saturday, including at brewers.com, where fans can make their purchases from the warmth of their homes.

• The Brewers returned catcher Rafael Neda to Minor League camp on Thursday.