Roenicke appeared in 27 games in his first season with the Orioles in 1978. A year later, in his first full season, he had perhaps the best season of his career, appearing in 133 games and hitting .261 with 25 home runs and 64 runs batted in. He even made the top ten in at-bats per home run, with one home run every 15.0 AB. The next year, he hit .239 with 10 home runs, 28 runs batted in. In 1981 he hit .269, but his power numbers were still significantly down, slugging only .384, whereas he had slugged .508 in his rookie season. In 1982, he hit .270 with a slugging percentage of .499 in 137 games, platooning with John Lowenstein and Benny Ayala.
Roenicke never established numbers like the 1982 season or rookie season. A year later, both his average and slugging were down and after two more years, the Orioles traded him to the New York Yankees for Rex Hudler. On the Yankees, his role was limited to a bench player and his power was down, with three home runs. He signed as a free agent in 1986 by the Atlanta Braves for less than half the amount of money he had been making ($380,000). He continued his career on the bench, this year doing better in the power department, hitting nine home runs. The next year, he hit .228 with a .298 slugging percentage, the worst of his career. He was released by the Braves on July 26, 1988 and retired.