Hideaki Wakui left his start against the Nippon Ham Fighters at ZOZO Marine Stadium after he gave up a single to the first batter he faced in the sixth inning. He first seemed to have problems with his left thumb. He left the field for treatment and returned. But after he finished throwing some warm-up pitches, he appeared to have an issue with his right leg. That was when he was pulled from the game.
Wakui had a perfect game through the first four innings. He gave up a lead-off single in the fifth before retiring the side in order. He left the game after he faced seventeen batters and threw seventy pitches.
Source: Nikkan Sports 9/24/2017
[UPDATE 9/25 @ 1:32am]
Wakui first left the field to get treatment for a cramp near the base of his left thumb. After he returned and threw some warm-up pitches, he developed a cramp in his left calf.
Source: Sanspo 9/24/2017