Bush had to leave Monday night's 25-22 victory over San Francisco in the fourth quarter with an injured right leg.
The Saints did not know the severity of the injury immediately after the game. Bush had an ice bag wrapped around his right leg in the locker room and was using crutches to get around.
"I'm just trying not to think the worst and just try to stay as positive as I can in this situation," Bush said. "That's all you can do, hope for the best."
Bush said he would likely get X-rays after the team returned to New Orleans.
Bush hurt himself after recovering his muffed punt with 6:58 remaining. He had trouble catching the ball at windy Candlestick Park and was hurt diving to cover up the loose ball.
"Last second it kind of shifted a little bit, just enough for me to drop it," he said. "I tried to recover it and somebody took my leg out. I don't know who it was, what happened or how it happened. I just know my leg got taken out. That's it."
He was tended to by trainers and then tried to walk off the field favoring his right leg. He fell back to the turf and was worked on again before being helped off the field.
"It hurt like hell," he said. "When I got back up and tried to walk on it, it felt terrible. That's all I can say."
Bush was taken on a cart to the locker room shortly after the injury, getting hugs from his teammates. Owner Tom Benson came up to Bush in the locker room to offer words of encouragement as well.
The injury capped a difficult past few days for Bush, who gave back his Heisman Trophy last Tuesday. The NCAA punished USC after concluding that Bush and his family took money and gifts from sports agents while Bush played for the Trojans. Bush said he returned the award to end the controversy.
"It's been a pretty tough week," he said. "It's just the way life goes."
There were some highlights for Bush in his first game since giving back the trophy. He caught a 6-yard touchdown pass on New Orleans' opening drive and set up a field goal with a 43-yard punt return on the final play of the third quarter.
Bush finished with 4 yards on five carries. He also had 30 yards on four receptions, including the touchdown.
The Associated Press contributed to this report