The striker has shaken off the thigh injury which has limited his impact on West Ham's season after joining the London strugglers on loan in January.
And Ireland assistant manager Marco Tardelli said of all the players in the squad, which is now down to 26 following Leon Best's withdrawal, it was the skipper who had impressed most on the training ground.
Point to prove: Robbie Keane hopes international football can kick-start his club season
Tardelli, the coach who ended the young Keane's ill-fated Inter Milan experience, said Ireland's record goalscorer was fully fit to lead the side out at the Aviva Stadium on Saturday.
Keane missed last month's friendly win over Wales and was initially rated doubtful for this weekend's clash. His chances were boosted, though, when he scored for The Hammers' reserves last week.
And Tardelli said: 'I think Robbie Keane has caught the eye because he has been out of action for many days with his injury. I have found him fit and there has been smile on his face which everyone around the squad can see. And he is in good form.
'It will be a good motivation for him to take out the frustrations of this season on Macedonia, but there is still a long way to go in the Premier League.
'I do think this is a good chance for him to play well. Because of his experience, Robbie Keane is very important for us.
Rare Hammer time: Keane has been dogged by injury since linking up with West Ham
'We have many options but I think it is possible for Robbie to play. He is fit to play a full match but for now and the future we have good options in Jon Walters and Shane Long, who has already played in a very important match in Slovakia.
'This match is very important. Maybe we dropped a point at home but against Slovakia, who are a very tough team, we played very well. Now it is very important for us to play well again.'
The sight of a resurgent Keane buzzing round the Malahide training pitch has clearly buoyed Giovanni Trapattoni and his coaching staff, but there was mixed news regarding the rest of the squad.
Deliver: Giovanni Trapattoni wants his Irish players to pull out all the stops
Although Leon Best did train in the shadow team on Wednesday morning, with Keane and Kevin Doyle playing as the leading strike partnership, he took a late knock to his ankle and decided to sit out the final shooting practice. Three hours later, the FAI announced the Newcastle striker had left the squad to return to Tyneside.
Despite his six Premier League goals since his extended run as Andy Carroll's replacement started, the former Coventry striker was likely to be fifth choice striker for both this week's games, behind the first choice pair, Long and Walters.
Walters, whose wife is still waiting to give birth, has yet to join up with the squad, just as Damien Duff has yet to train, after again staying at the team hotel for treatment and massages rather than make the short trip to Gannon Park.
Sean St Ledger, whose knee is still sore after he suffered a knock on Tuesday, remained on the bench for the sessions on Wednesday.
But after flying in on Tuesday night, Richard Dunne and Darron Gibson managed to train, showing no ill-effects of the shoulder and toe problems which left them doubtful for the weekend.?
?Baird handed Northern Ireland captaincy for 50th cap against SerbiaIreland stalwart Kilbane keen to avoid more Macedonia miseryWe don't want England rejects, blasts Republic of Ireland's Lawrence
?Explore more:People: Kevin Doyle, Robbie Keane, Damien Duff, Andy Carroll, Richard Dunne, Leon Best Places: Newcastle, London, Republic of Ireland, Macedonia, Wales, Ireland
Source: Daily Mail
Source: Daily Mail