Bush was injured while trying to field a punt in the Saints' 25-22 win over the San Francisco 49ers on Monday night.
"I tried to recover it (the muffed punt) and someone took my leg out," Bush told reporters after the game. "I don't know what happened or how it happened, I just got taken out."
He left Candlestick Park on crutches and said he did not know the extent of the injury.
"I just know it hurts," Bush said. "It's just in the middle (of the leg) but we'll see what happens."
The Saints said they would have no comment on the injury on Tuesday.
The injury comes less than a week after Bush forfeited the Heisman Trophy he won in 2005 while competing for the University of Southern California.
The National Collegiate Athletic Association (NCAA) penalized the school after reports that Bush, in violation of collegiate rules, accepted money and other benefits from marketing agents.
Bush has denied any wrongdoing, saying he returned the trophy given annually to the best player in college football because he wanted to end the controversy.
(Reporting by Gene Cherry in Raleigh, North Carolina; Editing by Steve Ginsburg; To query or comment on this story email firstname.lastname@example.org)