The Buckeyes got the win, but Justin Fields was banged up in the process.
Midway through Ohio State's 22-10 win over Northwestern, Fields began to show apparent discomfort in his right thumb on his throwing hand.
After the game, Fields told the Fox broadcast that he believes he suffered a sprain and will likely undergo more tests to determine the severity later this week.
"I think it might be sprained," Fields said. "I'm not sure, I'll probably get an X-ray on it or something like that, but I was just trying to finish out the game."
Fields went into more detail in his postgame press conference, revealing that he wasn't able to move his thumb and it made throwing the football difficult after the injury.
"It's pretty stiff right now. I really can't move it," Fields said. “I told Coach, I really couldn't throw the ball.”
Fields did not leave the game at any point but did require some medical tape on the sideline. He was able to finish the game and made several long throws down the stretch.
After the victory, Ohio State will now have just under two weeks until the College Football Playoff, should the Buckeyes make the four-team field. Fields hopes that will give him enough time to heal before a first-round game.
"Hopefully we have a good amount of time so I can get it recovered and healed up," Fields said.