The 31-year-old was sent for a scan today after complaining of soreness in his abductor muscle following his return from last night's 2-0 victory in Andorra, although manager Giovanni Trapattoni suggested that was precautionary.

However, the Football Association of Ireland this evening confirmed that his participation in the game could be under threat.

A spokesman said: "Following a medical update after training, Giovanni Trapattoni has said that Robbie Keane is a strong doubt ahead of Tuesday's match against Armenia."

If Keane does not make it, that will represent a huge blow to Ireland as they attempt to claim the point they need to book a play-off place.

The LA Galaxy frontman is his country's record international scorer with 51 goals, although he passed up a series of chances to add to his tally last night.

Keane has embarked upon a series of gruelling trans-Atlantic journeys to play for the Republic since heading to the United States, although he insisted earlier this week that he is feeling no ill effects.

One positive for Trapattoni is that his preferred strike-partner for his skipper, Kevin Doyle, looked to be back to his best last night after regaining his match sharpness following a knee problem, while Jonathan Walters also linked up with the squad today after recovering from an ankle injury.

The free-scoring Armenians stand between Trapattoni's Republic and a place in the play-offs in after Russia effectively ended their hopes of snatching automatic qualification by beating Slovakia.

Should the Russians beat Andorra in Moscow on Tuesday, even victory for the Irish will secure only second place in Group B.

Barring a shock of monumental proportions, Trapattoni's men seem likely to have to be satisfied with yet another play-off adventure, and a point against Armenia would keep the group's dark horses at bay.

The Armenians, who lost 1-0 at home to Ireland in the first round of qualifiers in September last year, have won each of their last three games, against Andorra, Slovakia and Macedonia, and scored 11 goals in the process.

But asked if he had been surprised by their late surge, Trapattoni said: "No. Maybe if you know the players who play for Armenia, it is not a surprise.

"The Armenian players play in strong leagues, and some of our players play in the Championship.

"If you think about it, it is no surprise.

"We must play with 100% mentality and 100% attitude and 100% concentration, and be careful of silly mistakes.

"We are in this position because of one or two silly mistakes against Russia, for example.

"Armenia is a very, very strong team. They have scored more goals than us and we must pay very, very much attention."

The 72-year-old Italian will send his team into their final group game with his own future still undecided amid speculation that he will be offered an extended contract should he guide them to the play-offs.

However, as his second qualifying campaign draws to a close - the first ended in a controversial aggregate defeat by France which denied him a trip to the World Cup in South Africa - Trapattoni is confident significant progress has been made.

He said: "At this stage, I hope I have succeeded in instilling a mentality in our players.

"Unfortunately, I am quite demanding because in the past, I have built this mentality with teams I have previously managed.

"I am very pleased with our way, but we can improve again.

"Yesterday evening, I said we want to look at Manchester United. Obviously, we do not have the players of Manchester United, but with their mentality, with attitude, with balance, I think we can achieve."

Ireland's Rugby World Cup exit was unfolding as Trapattoni and his players touched down in Dublin during the early hours of this morning following a gruelling trip back from Andorra.

Trapattoni said: "I am sorry that Ireland lost in rugby against Wales because Brian O'Driscoll and his team are our friends and we wished them to do well.

"But sport is sport and it teaches us that when we have the right mentality, we can achieve every result."

The nation had been swathed in optimism in the run-up to the quarter-final, but as O'Driscoll and his team-mates prepare to head home, attention will turn to their football counterparts once again.

However, that is a pressure Trapattoni is happy to take on.

He said: "In the first qualifying campaign for the World Cup, we deserved to achieve the minimum of a play-off place.

"You saw the games against France and with a bit of luck - or without bad luck - we could have achieved this.

"We feel this pressure. No, it's not pressure, it is commitment."

Left-back Stephen Ward is suspended for Tuesday's game as a result of his second booking of the competition, but Richard Dunne is available after completing his ban.