The new mechanics provided powerful results. Yahn, 5 feet 11, 185 pounds, did not hit a home run in his first two pro seasons, a string that reached 549 plate appearances before he connected for Frederick on May 1. Then he hit five homers in less than a month. In 56 games, he was hitting .296 with 13 doubles and 35 RBI, maintaining his UConn trademarks — flowing hair, free swinging and a knack for getting his uniform filthy by the second inning. He had a single and a two-run double in the Carolina League’s All-Star Game before his home crowd in Frederick, Md.