Ronaldo, the World Cup-winning former Brazil international, will come out of retirement to play for Fort Lauderdale Strikers.
The 38-year-old hung up his boots in 2011, but has been tempted to return in the second-tier North American Soccer League with Fort Lauderdale, where he is part-owner.
"It's going to happen," Ronaldo confirmed to Lance!, a Brazilian newspaper.
"I have already said so. But it's going to be a bit later, in the playoffs."
Ronaldo helped Brazil win the 2002 World Cup and was named FIFA World Player of the Year three times.