A football fan appeared to deliberately jump from the upper deck at the Oakland Coliseum during an NFL game between the Raiders and Denver Broncos, police said Friday. Police initially called the Thursday night fall an accident. But a preliminary investigation revealed the man either jumped or climbed over a wall on the third deck and fell to the concrete of the lower concourse moments after kickoff, Oakland police Sgt. Chris Bolton said Friday. The man was treated at the scene by emergency personnel and taken to a hospital where he was listed in serious condition with non-life threatening injuries, police said. Eyewitness accounts were inconsistent, but Bolton said the incident was not the result of foul play. "This is not a criminal investigation, and no follow-up is being done in connection to a criminal case," Bolton said. The man's name has not been released. It is also not known if alcohol may have been a factor. The Raiders issued a statement late Thursday. "Our thoughts and prayers are with this gentleman and his family and friends," the team said.