Investigators interviewed nine people injured in the brawl at the end of the Pistons-Pacers game, but no charges were imminent in the case, the county prosecutor said.
Police were also reviewing videotapes and interviewing wit-nesses from Friday night's melee, when Indiana forward Ron Artest charged into the stands after a fan threw a cup at him.
If charges are filed, they probably would be for assault and battery, a misdemeanor that could bring a three-month jail sentence, David Gorcyca, the Oakland County prosecutor, said on Monday. The only possible felony charge could be against the person who hurled a chair into the crowd.
Police Chief Doreen Olko said none of the people involved was seriously injured.
Asked if Artest could claim self-defense, Gorcyca said: "Even if someone did throw water, you don't have a license or a green light to punch them."
John Green of West Bloomfield Township was the fan who threw the cup at Artest, Gorcyca said. The prosecutor identified Green -- a former next-door neighbor -- by repeatedly watching footage of the brawl. He said footage showed that once Artest was in the stands, Green grabbed him from behind and sucker-punched him.
Green, however, told reporters he didn't throw the cup.
"I wish the whole thing didn't happen," he said.
"I'm sure the NBA players that got involved in it wish it never happened, the fans never wished that it had happened. I know I don't. It was awful, it was ugly," he said.
Pistons chief executive Tom Wilson said Green is a season-ticket holder and will be banned from The Palace.
On Sunday, the NBA suspended Artest for the rest of the season. The league also suspended Indiana's Stephen Jackson for 30 games and teammate Jermaine O'Neal for 25. Detroit's Ben Wallace -- whose shove of Artest after a foul led to the five-minute fracas -- drew a six-game ban, while Pacers guard Anthony Johnson got five games.