Cincinnati Bengals quarterback Joe Burrow has revealed his appendectomy last month was more serious than first thought after his appendix ruptured.

Burrow returned to training on Sunday after undergoing an appendectomy on July 26, giving him four weeks to build up before the Bengals' NFL season opener against the Pittsburgh Steelers on September 11.

The 25-year-old quarterback, who was due to return to team drills on Wednesday, revealed the extent of the issue when addressing a press conference for the first time since the surgery.

"It wasn't normal appendicitis that you hear about," Burrow said.

"I didn't really feel much. Just getting checked out and had some discomfort so we thought we'd get it checked out.

"Turns out I had it, so we had to get it fixed. Not ideal timing obviously but glad to have it now than halfway through the year."

Burrow was sidelined longer than most players for an appendectomy which typically means only missing a few days.

The Bengals are confident the 2020 NFL Draft top pick will be fit and healthy to face the Steelers but Burrow said there was plenty of work to do to ramp up, having lost weight in hospital.

"When they cut into you and do all that stuff your core is going to lose some muscle and some strength just getting that back," said Burrow, whose 2020 and 2021 preseasons were interrupted by COVID-19 and knee surgery respectively.

"I'd like to have a normal offseason at some point. That would be great. Going into the season feeling as good as I can, but that hasn't been the reality for three years."

Burrow, however, is not expecting to play in the Bengals' preseason.

"I think it will be OK," Burrow said. "We have a good plan as far as nutrition and weight room and all that stuff.

"I feel good right now and just going to keep feeling better."