Last year, in his first full major league season, righthander Jimmy Haynes won II games and struck out 134 batters. Acquired from the Orioles in a June 1997 trade for Geronimo Berroa, the 6'3", 180-pound Haynes has a five-pitch repertoire that includes a 94-mph fastball. He has struggled with his control-last year he walked 88-but with another solid season Haynes should be poised to join Oakland's long list of burgeoning stars. "We've already developed a lot of young players on this team," says manager Art Howe. "The next step will be to do that with the pitching staff, and that all starts with guys like Jimmy Haynes."