Ruthven charged from the gate in 1981, compiling an 8-3 record before the 1981 baseball strike began on June 12. He was the Phillies' representative to the Major League Baseball Players Association. Because of his record, Ruthven was named to the National League All-Star team for the second time. Play resumed on August 10; Ruthven told reporters, "I played catch a little bit during the strike. I don't think I'm that far away. But I've never stopped in the middle of the season, just like anyone else, and I really don't know how long it will take" to get back to form. He struggled for the remainder of the season, going 4-4 the rest of the way. For the season, Ruthven finished 12-7 with a high 5.15 earned run average. Because of the strike, major league baseball split the 1981 season, and two teams from each division made an extra round of playoffs. The Phillies "won" the first-half title, though lost the 1981 National League Division Series to the Montreal Expos in five games, with Ruthven losing Game 2 to the Expos.