WHEN HE WAS nine Bruce was such a big fan of Ken Griffey Jr. that he called up the Kingdome in Seattle from his Beaumont, Texas, home and asked to speak to the then Mariners star. "Didn't get past the switchboard operator," he says. If Bruce, who turns 21 next week, isn't regularly playing alongside Griffey in Cincinnati's outfield this summer, it won't be because he hasn't proved himself in the minors. Last year Baseball America's top prospect had 80 extra-base hits across three minor league levels and slugged .567 in 50 games with Triple A Louisville. This spring he had a chance to win the starting job in centerfield until he strained his left quadriceps. He'll start the season in Triple A, but he impressed the Reds brass in his first big league camp. He also finally got to talk to Griffey, regularly picking his brain for pointers. "I hope I haven't annoyed him too much," Bruce says. "He's always been my idol. It's weird to think that soon, hopefully, he'll be my teammate too."