On one occasion last month, Asheville hitters were hammering away against West Virginia Power pitching - until Amaury Rivas arrived from the bullpen.

Facing a Rivas fastball that sometimes reached 95 mph, the Asheville hitters suddenly found themselves unable to hammer away. The imposing velocity made a noticeable difference, especially in the Class A South Atlantic League, and induced weak pop-ups.

"They couldn't get their bat head through to get on top of those pitches,'' recalled Power pitching coach John Curtis.

After missing virtually all of last year because of Tommy John elbow surgery, Rivas, a 22-year-old Dominican Republic native, is quickly making his case as a big-league prospect, a hard-throwing right-hander whose slider, says Curtis, is already big-league quality.

For now, however, those 95-mph fastballs too often arrive high in the strike zone and, as he moves up the professional baseball ladder, Rivas will need to locate those deliveries mostly at knee level.

Nevertheless, Curtis likes Rivas' velocity, his ability to throw strikes, his bulldog approach and his slider, which darts down and away from right-handed hitters.

"If we had a must-win game today,'' said Curtis, "he would pitch. He's been our most effective starter, as far as dependability. So far, in his good outings, his fastball has been so strong that [hitters] can't get around on him.''

As a pitcher bouncing back from major surgery, Rivas will be somewhat limited in his workload this season and is alternating between starter and reliever. In 30 innings, he's 3-1 with a 2.67 ERA and has allowed just 25 hits and seven walks in 30 innings.

On one occasion last month, Asheville hitters were hammering away against West Virginia Power pitching - until Amaury Rivas arrived from the bullpen.

Facing a Rivas fastball that sometimes reached 95 mph, the Asheville hitters suddenly found themselves unable to hammer away. The imposing velocity made a noticeable difference, especially in the Class A South Atlantic League, and induced weak pop-ups.

"They couldn't get their bat head through to get on top of those pitches,'' recalled Power pitching coach John Curtis.

After missing virtually all of last year because of Tommy John elbow surgery, Rivas, a 22-year-old Dominican Republic native, is quickly making his case as a big-league prospect, a hard-throwing right-hander whose slider, says Curtis, is already big-league quality.

For now, however, those 95-mph fastballs too often arrive high in the strike zone and, as he moves up the professional baseball ladder, Rivas will need to locate those deliveries mostly at knee level.

Nevertheless, Curtis likes Rivas' velocity, his ability to throw strikes, his bulldog approach and his slider, which darts down and away from right-handed hitters.

"If we had a must-win game today,'' said Curtis, "he would pitch. He's been our most effective starter, as far as dependability. So far, in his good outings, his fastball has been so strong that [hitters] can't get around on him.''

As a pitcher bouncing back from major surgery, Rivas will be somewhat limited in his workload this season and is alternating between starter and reliever. In 30 innings, he's 3-1 with a 2.67 ERA and has allowed just 25 hits and seven walks in 30 innings.

The parent Milwaukee Brewers feel no need to rush him through the system, especially in light of last year's surgery, but Curtis sees realistic big-league possibilities.

 "Right now, given the pitches he has, I would probably see him as a situational reliever or a possible back-end-of-the-rotation starter,'' said Curtis. "He has a lot of work to do on his changeup and maybe he needs to introduce a fourth pitch.''

Rivas throws his changeup and slider, Curtis noted, at the same speed - a shortcoming that allows hitters a better opportunity to time his pitches - and he sometimes focuses too intently on the hitters and ignores the baserunners.

In addition, the energetic Rivas runs the risk of wearing himself out.   

"Amaury's only problem is that he is so full of excitement that he really doesn't have an inner governor that says, 'OK, I need to rest today,' '' said the Power pitching coach. "His enthusiasm just carries him day by day.''

POWER POINTS: Before the season, Baseball America rated Rivas as the Brewers' No. 11 prospect. ... Although Rivas is likely to stay in Charleston for the full season, Mike Ramlow has positioned himself for a promotion to Brevard County of the Class A Florida State League. The 6-foot-6 left-hander has struck out 28 in 25 innings and has posted a 3.60 ERA. "Ramlow has been just awesome,'' said Curtis. "I don't expect him to be here a whole lot longer.'' Ramlow, who compiled a 6.11 ERA with the Power last year, also has impressed manager Jeff Isom. "Ramlow's really emerged,'' said Isom. "He's pitching with confidence and running that fastball up there at 90 miles an hour from the left side.'' ... The Power keeps statistics on such things as percentage of fastballs thrown for strikes. Nick Tyson, who has walked just three batters in 21 innings, leads the team at 69 percent. An average of 60 percent is considered good. Some fastballs, of course, are thrown intentionally off the plate in hopes of inducing swings. ... The recent knee injury suffered by Yovani Gallardo, who pitched for the 2005 Power, probably will keep him out for the season. Gallardo suffered a torn ligament covering first base against the Cubs May 1.

To contact staff writer Mike Whiteford, use e-mail or call 348-7948.