The 29-year-old forward has missed Portugal's previous two warm-up matches through injury, hindering their preparations for the Brazil tournament and sparking speculation that he might not be fit in time.
But the Real Madrid ace returned to training on Saturday with Paulo Bento's side, who have failed to sparkle in their captain's absence.
Portuguese officials were tight-lipped Sunday about Ronaldo's availability for the Ireland encounter, but forward Vieirinha told reporters: "If he is fit to train, he is fit to play the match."
Bento has been keen to stress that Portugal -- who only made it to Brazil via a play-off with Sweden that saw Ronaldo fire a hat-trick -- are more than just one player.
But Wolfsburg man Vieirinha admitted their star player's return had buoyed the whole squad.
"Everybody knows the importance of Ronaldo to our team and his importance to the group, both on and off the pitch," said Vieirinha, 28.
Ronaldo has scored 49 goals in 110 matches for Portugal.
Last weekend they labored to a 0-0 draw in Lisbon against fellow World Cup qualifiers Greece.
Then on Friday, near Boston, they survived several scares before beating Mexico -- who will also be in Brazil -- 1-0 thanks to an injury-time header from Bruno Alves.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
