In 1979, the first of two times he would play on an AL pennant winner, Flanagan's 23 victories led the circuit and earned him the league's Cy Young Award. He was a member of the Orioles' World Series Championship team in 1983. He returned to Baltimore to close out his playing career as a reliever in 1991 and 1992. During this second tour, he contributed to the most recent no-hitter thrown by the club. He was also the last Orioles pitcher to appear in a major-league contest at Memorial Stadium.

This Rawlings official MLB baseball was signed in blue by Flanagan and inscribed, "83 W.S. Champ." This baseball includes a MLB hologram.