Walker was diagnosed with a facial contusion after exiting Thursday's win over the Reds, Steve Gilbert of MLB.com reports.
Walker was hit in the head by a pitch in the top of the eighth inning Thursday, and he immediately left the game. While the 31-year-old will likely be monitored ahead of Friday's matchup against Philadelphia, he seems to have avoided a significant injury. If Walker misses any additional time, Pavin Smith and Jordan Luplow are candidates to fill in at first base.