Grzenda played the final 30 games of his career during the 1972 season, going 1-0 with a 5.66 earned run average over 35 innings.
For his career he pitched in 219 games, all but three of them out of the bullpen for the Detroit Tigers, KC Athletics, New York Mets, Minnesota Twins, Washington Senators and Cardinals.
He posted a 14-13 lifetime record with an ERA at 4.00 on the nose, with 173 strikeouts in 308 innings pitched.