Brian Windhorst details an incident in which Raptors president of basketball operations Masai Ujiri made contact with an officer while trying to get on the court. (1:17)

SAN FRANCISCO -- A deputy suffered a concussion and is on medical leave after an altercation with the president of the Toronto Raptors as he tried to join his team on the court to celebrate their NBA championship, a lawyer said Tuesday.

The 20-year-veteran of the Alameda County Sheriff's Office also has a serious jaw injury and is considering filing a lawsuit against Raptors President Masai Ujiri, attorney David Mastagni said.

"The officer is off work, disabled and wants to go back to work," Mastagni said. The name of the deputy has not been released.

The clash between the deputy and Ujiri happened as the deputy checked court-access credentials after the game Thursday in Oakland against the Golden State Warriors.

Authorities say Ujiri tried to walk past the deputy but the deputy stopped him because he didn't see Ujiri's on-court credentials.

Ujiri pushed the deputy, who pushed him back before Ujiri "made a second, more significant shove and during that shove his arm struck our deputy in the side of the head," sheriff's Sgt. Ray Kelly said. He said Ujiri also shouted obscenities.

Several bystanders intervened and Ujiri got onto the court without displaying any credentials, Kelly said.

Investigators were questioning witnesses and the office hopes to file a report to prosecutors this week recommending a misdemeanor battery charge against Ujiri, Kelly said.

They are also reviewing footage from body cameras worn by the deputy along with footage from the arena surveillance system and cellphones.

The office does not plan to release the deputy's body camera footage to the public during the investigation, Kelly said.

Kelly confirmed the officer is on medical leave.

The Raptors said last week the team was cooperating with the investigation and gathering information on its own. It had no further comment Tuesday.

Warriors fan Greg Wiener, who witnessed the altercation, said last week the incident began when the deputy put his hand on Ujiri's chest and pushed him. Ujiri shoved him back before bystanders intervened, Wiener said.

He also said then that there was no conversation between the deputy and Ujiri. But on Tuesday, he said he remembered the officer shouting, "No one gets on the court without credentials."

Wiener said he recalled the detail "after thinking about it all weekend."