MINOR LEAGUES / SEAN WATERS : Cream of the Crop Rises to Top : Baseball: Prospects get a chance to show their stuff with major league teams.

For some minor league baseball players, Sept. 1 can be as exciting as Christmas morning. Starting today, major league teams can expand their rosters to 40 players and a few select minor leaguers will be rewarded with promotions.

Pennant contenders, such as the Dodgers and the New York Mets, will be adding reserves to help the battle for a playoff spot.

Other teams will use their additional roster spots to test their top prospects against major league competition.

Third baseman Chris Donnels (South Torrance High, Loyola Marymount), catcher Kelly Mann (Culver City), outfielder Brad Bierley (Rolling Hills), third baseman Joe Redfield (Miraleste) and outfielder Eric Bullock (Harbor College) are among the minor leaguers from the South Bay-area who might be promoted.

The New York Mets need a replacement for shortstop Kevin Elster, who will miss the remainder of the season because of tendinitis in his right shoulder. Elster was placed on the disabled list Wednesday and will undergo surgery next week.

Howard Johnson recently replaced Elster at shortstop and the Mets have rotated journeyman Tom O’Malley and Gregg Jeffries at third base.

Donnels, who began the season on the New York’s 40-man roster, had 10 home runs and 11 stolen bases for the Jackson (Miss.) Mets in double-A.

Despite consistently hitting below .200 for the Richmond Braves in triple-A, Mann has the defensive skills to become a top catcher in the major leagues. The Braves need a replacement for veteran Ernie Whitt, the free agent who flopped after signing a multi-year contract with the team in the off-season.

Bullock (Indianapolis), Bierley (Iowa) and Redfield (Denver) had good seasons at the triple-A level and might be called up by the Montreal Expos, Chicago Cubs and Milwaukee Brewers, respectively.

Bullock earned the distinction as the first South Bay-area player to be called up this season when he replaced veteran outfielder Tim Raines on the Expos’ roster in June.

Although veteran outfielder Kal Daniels has been hampered by back pains, it’s doubtful the Dodgers will promote Billy Bean despite the fact the former Loyola Marymount standout has been hitting close to .300 for the Albuquerque Dukes.

An award-winning week--For the second consecutive week, a third baseman from the South Bay has been honored as Player of the Week by Howe Sportsdata International.

Sean Berry, the former West Torrance standout, was honored this week as the top hitter in the Southern League (double-A). Berry went 10 for 22, including three doubles and a home run for the Memphis (Tenn.) Chicks. He scored four runs and had 10 runs batted in. He had a batting average of .455 and slugging percentage of .727.

Last week, Ken Pennington (El Camino College) was selected the top hitter in the Eastern League.

Pennington had 10 hits, including two home runs and seven RBIs for the Williamsport (Penn.) Bills, a double-A affiliate of the Seattle Mariners. He raised his batting average from .244 to .257.

Seattle considers Pennington its third baseman of the future. The Mariners traded veteran third baseman Jim Presley to Atlanta for Pennington and pitcher Gary Eave during the off-season. Eave was later dealt to the San Francisco Giants for pitcher Russ Swan.

Still a star--San Jose Giants shortstop Royce Clayton (St. Bernard) was selected to the 1990 California League All-Star team.

Salinas pitcher Steve Maye, who lead the league in complete games; second baseman Brian Turang (Loyola Marymount), and outfielder Dan Lewis (El Camino) received honorable mention.

California League managers also picked the best players for 21 hitting and pitching categories. Clayton earned the most honors for South Bay players, being selected as the infielder with the best arm and best defensive shortstop.

Rick Davis (Cal State Dominguez Hills) finished in a tie for second as the best fielding pitcher and Turang received votes for being best defensive second baseman.

Clayton, along with Turang and Lewis, were also nominated as most improved player.