Geno Smith cleared a concussion evaluation early in the second half against the Bills on Sunday, but he returned to the sideline medical tent after playing one drive in the third quarter.
Smith led the Jets to their fourth field goal of the day before giving way to Cade Klubnik for the second time of the day. The fourth-round pick was able to lead the Jets to three points the first time he came into the game, but his second drive was less successful.
Smith eventually returned to the locker room and the Jets announced he has an ankle injury.
Klubnik fired high to Garrett Wilson and Bills cornerback Davison Igbinosun picked the ball off, but wound up losing it after a hit from Jets tight end Jeremy Ruckert. The Jets recovered the ball, but wound up punting a few plays later and trail 24-12 at the end of the third quarter.