Bradley stayed face down on the ground for several minutes Tuesday night as trainers attended to him and teammates squatted near the mound. Trainers rolled Bradley onto his back and moments later helped him to his feet. He walked off the field under his own power and gave a thumbs up to the crowd.
Bradley held a towel over his mouth, nose and swollen cheek as he headed toward the dugout. He left the game with Arizona leading 3-0 and one out in the second inning.
The 22-year-old Bradley, a prized rookie, entered 2-0 with a 1.45 ERA in three starts. His first two major league wins came this season against Los Angeles Dodgers ace Clayton Kershaw.
Bradley was selected seventh overall by Arizona in the 2011 amateur draft.