Entering halftime against the Buffalo Bills on Sunday, the New York Jets surprisingly trailed by just four points, 10-6.

However, on the final drive of the half, Jets quarterback Geno Smith took a tough hit as he released the ball. He remained on the ground before making his way to the Jets’ sideline.

According to the Jets, Smith is currently being evaluated for a concussion.

As Smith is being evaluated, fourth-round rookie quarterback Cade Klubnik will make his NFL debut to open the second half. Klubnik, whom the Jets selected out of Clemson in April, won the Jets’ QB2 job over the summer, beating out Bailey Zappe and Brady Cook.

Now he gets his first opportunity in the regular season, and it comes at a big moment. The Jets are down by just four points, and he has a chance to make a loud statement in his first appearance.

In Smith’s case, concussion protocol is tricky. He is questionable to return, but given the league’s protocol, it’s certainly not a lock that he will be cleared to return today against Buffalo.

On Klubnik’s opening drive, he looked solid. The rookie completed two of his first four passes for 39 yards, while picking up 19 more on the ground over two rushes. He led the Jets to another field-goal drive, making the score 10-9 in favor of Buffalo, while also finding Garrett Wilson for 29 yards on his first attempt.