Brazil coach Dunga praised Ronaldo's progress in his latest comeback and said on Thursday the national team door was open for the 32-year-old striker.
"I've said already that the national team doors are open for any player who is technically good enough," Dunga told a news conference.
"He is certainly in excellent form and is being watched by the technical staff.
Ronaldo has scored 10 goals in 13 games for Corinthians since recovering from last year's knee injury at AC Milan and joining the Sao Paulo-based club.
The former AC Milan, Inter Milan, Barcelona and Real Madrid striker has not played for Brazil since the 2006 World Cup, having been plagued by fitness and form problems.
"It's the first time since 2006 that he has managed to play more than 10 games in a row, so the trend is for him to progress.
"Ronaldo has never stopped scoring goals," Dunga added. "He knows his potential. There is one year between now and the World Cup for everyone to work and earn a chance."
Brazil's next games are the World Cup qualifiers away to Uruguay and at home to Paraguay next month. Dunga is due to name his squad on May 21.