"Holy concrete wall, Batman!"
McKenzie, who plays young Det. Gordon in Fox's upcoming Batman origin story, was injured on the show's set Friday (his birthday) while he was shooting a fight sequence.
The actor posted three photos on Instagram — one of which showed his head bleeding and the other with him giving a thumbs-up while appearing to get stitches.
"Happy Birthday to me," McKenzie captioned one. "Fight sequence gone awry. Don't ram your head into concrete pillars kids. #gotham."
McKenzie says he'll be back to work on Monday.
On the Set: Gotham's stunt coordinator teaches us how to fake a fight: