Buffalo quarterback Kevin Kolb was treated for concussion-like symptoms after getting kneed in the back of the helmet in the Bills' preseason game Saturday against the Washington Redskins.

Kolb was hurt at the end of an 8-yard scramble in the first quarter. He remained in the game for four more plays, until the drive ended with a 2-yard touchdown run by C.J. Spiller.

Washington won 30-7.

Kolb has been competing for the starting job with first-round pick EJ Manuel, but Manuel hurt his left knee in the Bills' previous game and is out for the rest of the preseason. Kolb was 2 for 4 for 16 yards and had two runs for 12 yards Saturday when he left the game.

With both Manuel and Kolb hurt, undrafted rookie Jeff Tuel became the only healthy quarterback on the roster. Tuel entered the game on the next series.

Kolb has suffered at least two concussions over six NFL seasons. Selected by the Philadelphia Eagles in the second round of the 2007 draft, he lost the starting job to Michael Vick when he was sidelined by a concussion in the season opener in 2010.

Kolb spent the past two seasons in Arizona, where he failed to secure the starting job because of an assortment of injuries, including a concussion in 2011. He switched to a new helmet the following year, one meant to gives addition protection to the back of his head.

The Bills also had two defensive backs leave with injuries in the first half. Da'Norris Searcy, who started at safety in place of Jairus Byrd, suffered a head injury. Starting cornerback Stephon Gillmore had a wrist injury.

Byrd was on the sideline but did not suit up. The two-time Pro Bowl safety joined the team this week after signing a one-year, $6.9 million franchise player tender, having missed all of the offseason practices and training camp.