 In , Oh only appeared in 4 games, posting a 1-1 record and a 4.61 ERA in 13.2 innings pitched.After the season, he joined the Korea Armed Forces Athletic Corps Baseball Team to serve two years of mandatory military service.In , Oh returned to the pro league after finishing the military duty but had a mediocre comeback season, posting a 1-2 record and 5 holds with a 4.08 ERA as a relief pitcher.