Hill was removed from Wednesday's game against the Nationals after colliding with the outfield wall, Lochlahn March of The Philadelphia Inquirer reports.
Hill leaped headfirst into the fence in center field while trying to make a catch in the 11th inning. After remaining on the ground for a few minutes, he was able to walk off the field under his own power. He'll presumably undergo further evaluation -- possibly for a concussion -- and the Phillies may provide more details on his status in the near future.