DeCinces began his major league career with the Baltimore Orioles late in the 1973 season, and he played for the Orioles in the ensuing eight full seasons. On June 22, 1979, in one of the most famous games in Orioles history, he hit a game-winning home run at Memorial Stadium off Detroit Tigers reliever Dave Tobik. The Orioles were trailing the Tigers 5-3 going into the bottom of the ninth inning. With one out, Ken Singleton hit a solo home run off Tobik to bring the Orioles within one. Eddie Murray reached base on a single, and, with two outs, DeCinces hit a two-run home run to give the Orioles a 6-5 victory. The win has been called "the night Oriole Magic was born."

This H&B Louisville Slugger B267 Doug DeCinces game model bat has a crack in the handle and DeCinces' uniform number "11" written in black marker on the knob. The barrel of the bat shows plenty of use as well, but it is unknown if it was used by DeCinces.