Buffalo Bills quarterback Kevin Kolb left his first start of the preseason after just two offensive series on Saturday with "concussion-like symptoms," the team announced.
Kolb took over as the Bills' starter after first-round pick E.J. Manuel underwent a "minor knee procedure" and was ruled out for the preseason.
Kolb completed two of his four pass attempts for 16 yards and ran twice for 12 yards during his brief time behind center. He sustained the head injury after being kneed in the head at the end of one of his runs.
Kolb has a history of concussions. Expected to be the Eagles' quarterback of the future, he suffered a concussion during the team's 2010 regular-season opener, which allowed Michael Vick to gain the starting job.
After being traded to the Cardinals, Kolb then missed the final month of the 2011 season with another concussion, which he later said lingered for three weeks after the season ended. He signed a two-year, $13-million contract with the Bills this offseason.