Ronaldo, 38, intends to turn out for NASL club Fort Lauderdale Strikers, which he part owns.
"It will happen. I already said that. But it will not happen until a little later in the season, during the playoffs," said Ronaldo.
The Brazilian last played in 2011 and is now undergoing a strict fitness schedule to get himself up to speed.
Former Real teammate Raul is also playing in the NASL this year with New York Cosmos.
For the big stories and the banter follow us on Twitter: @tribalfootball