If you want to fit into the Braves' rotation, you must have the arm and the intelligence. Lefty Bruce Chen has both. Chen, a 21-year-old Panamanian who boasts a fastball that tops out at 92 mph and a precocious ability to work the corners with his curve and changeup, bedeviled hitters at three levels last year, winning 17 games, including two in four starts in the majors. He's also a dean's-list student who's six semesters shy of a civil engineering degree from Georgia Tech. "He's a quick learner," says fellow Atlanta pitcher Kevin Millwood. "He's got great stuff, and anytime you put great stuff with a great head, you've got a chance to have a great pitcher."