The Argentine World Player of the Year collapsed to the turf after colliding with Benfica goalkeeper Artur late in the Group G clash at the Nou Camp, which ended 0-0, and was taken off on a stretcher in obvious pain.
A scan ruled out anything more serious than bruising and Messi worked out in the gym on Thursday.
"When I felt the blow I thought the worst because of the pain, that I might be out for many months," said the 25-year-old who came on as a substitute for the final half an hour with Barca already through to the last 16 as group winners.
"After the tests, and having ruled out a serious injury, I was much more relaxed," he said. "I am feeling good, fortunately it was only a blow and I am much better."
After his collision with Artur, Messi still managed to fire a shot away which the Benfica keeper saved on the line. "I thought it might be the last ball I kicked for a long time and I wanted to take the shot," Messi said.
"I don't know if I'll be available for Sunday, it depends on how things go. You won't notice [if I am out] because there are plenty of other players."
"I still think the same, that it could have happened in training or in any other match," Messi said. "Whenever you go on to the pitch there is a risk."
"Obviously it would be nice because it [the record] was set many years ago and I am close, but it doesn't worry me," he said.
Barca have three La Liga matches and the first leg of their King's Cup last 16 tie against Cordoba left to play in 2012.
