Green's 2006 season was put in jeopardy by a severe concussion he suffered during on September 10, 2006, against the Cincinnati Bengals in Kansas City. Green attempted to slide during a third-quarter play, but was hit hard by Cincinnati defensive end Robert Geathers, who had lowered his shoulders, but instead struck the quarterback in an unusual position. However, the official determined that no foul had been committed and Geathers insisted that he had tried to check up, but was pushed by Chiefs receiver Eddie Kennison. CBS announcer Randy Cross, a former offensive lineman with the San Francisco 49ers, believed the hit was unintentional and supported the officials' decision. National Football League officials took the same position and, on September 13, 2006, declined to fine Robert Geathers because he did not have complete control of his body. Green was rendered unconscious and the game was delayed for over fifteen minutes while he received medical attention. He reportedly regained consciousness in the tunnel and could not recall the play. According to Chiefs general manager Carl Peterson, preliminary doctor's visits revealed a "very, very severe concussion" and stated that Green would be out indefinitely.