Rookie Yuki Saito hobbled out of his fourth start for Hokkaido Nippon Ham as the Fighters lost 4-2 to the Softbank Hawks on Sunday.
Saito, who is 2-0 so far this season, was replaced after the first inning with pain in his left abdomen. He stayed at Sapporo Dome to receive treatment after being relieved by Kazuhito Tadano.
Saito had a 1-2-3 inning, retiring the side on 10 pitches. Hirotoshi Masui suffered his first loss of the year after allowing two runs in the ninth on veteran Hiroki Kokubo's two-RBI double.