This was really scary.
Jaguars linebacker Myles Jack saw his night end early in the second half after he took a knee to the helmet by Derrick Henry.
Footage shows the fourth-year defender momentarily knocked out cold on the field.
Jack was eventually taken to the sideline to be tested for a concussion. He did not return to the game.
Jack was signed to a four-year, $57 million extension this past summer.
