 Warren is one of many ballplayers who only appeared in the major leagues during World War II conflict.He made 22 pitching appearances for the Brooklyn Dodgers during the 1944 season, starting four of them and completing two, allowing 114 baserunners on 74 hits and 40 walks in just 68 innings.He also gave up 52 runs (14 unearned), while his lone win came on July 30, 1944 in the first game of a doubleheader at Ebbets Field, when he was the starting pitcher in a 10–4 victory against the St. Louis Cardinals.