Coach Frank Vogel says Hill was hurt after a collision with Knicks center Tyson Chandler during the first half of Indiana's 93-82 victory on Tuesday. Hill finished the game and scored 26 points as the Pacers took a 3-1 lead.
Hill had experienced headaches and showed concussion symptoms since and wasn't able to pass the league's concussion tests so he could play Thursday night.
Vogel says Hill is day to day and won't play again until he has passed the tests.
D.J. Augustin was to take the majority of Hill's minutes.
The Knicks also changed their lineup, reinserting guard Pablo Prigioni after going with a bigger lineup Tuesday.