The Napoli forward is a major doubt after injuring his thigh in Sunday’s friendly against Palermo.
“My injury has improved, but I have only been able to train on my own,” he said.
“I’ll only play only if I am totally fit, you can’t play in a game like this one if you are only 70% ready.”
Goalkeeper Jan Mucha, who saved a Robbie Keane penalty in the 1-1 draw in Zilina last October, warned his teammates that Keane is not the only dangerman in the side.
“I hope Ireland won’t take another penalty on Friday,” said the Everton reserve goalkeeper.
“I know Robbie is a great footballer and we all saw that he scored on his debut in the USA, but Ireland have more great players besides him.”
His teammate Marek Cech singled out his former West Brom colleagues Shane Long and Simon Cox as players to watch ahead of the crucial clash.
“I know that Shane and Simon are both excellent players, they are strong on the ball and can finish very well, and they are both very good in training too,” said Cech, who completed his move to Trabzonspor on Wednesday.
“I did not talk to them about the game, it’s not a joking matter for me. This match is very important for both sides, I’m not interested in making it into a joke.”
The Slovakia team travelled to Dublin on Wednesday with coach Vladimir Weiss handing winger Miroslav Stoch an ultimatum after he was kicked out of the last international squad against Austria for drink driving. The former Chelsea winger, now at crisis-hit Turkish side Fenerbahce, lost his licence and has been given one last chance by his coach.
“He made a big mistake but he has apologised for it,” said Weiss.
“I can forgive one mistake, but not another. He needs to get his feet back on the ground.”
Weiss was pleased that late transfer deals involving his players this week were completed before the team travelled to Ireland. His son, Vladimir Weiss Jnr, moved to Espanyol, while Peter Pekarik moved from Wolfsburg to Bursaspor.
Weiss Jnr was part of the Manchester City squad that played a pre-season tournament at the Aviva Stadium.
He said: “It’s a great arena and the fans are superb. We want to enjoy the game and at the same time, get a good result from it.”