Joe Allen’s bid for World Cup fitness has entered a critical period with Joe Ledley warning that his former Wales teammate must restrain himself in training.

Allen has not played since September 17 because of hamstring damage and is running out of time to be fit for Wales’ World Cup opener against the United States on Monday.

The Swansea midfielder has been primarily training on his own away from the main group, but Allen is so important to the way Wales function that boss Robert Page is desperate for the 32-year-old to play some part in the tournament.

Austria v Wales – 2018 FIFA World Cup Qualifying – Group D – Ernst Happel StadiumJoe Ledley (left) and Joe Allen (right) were midfield partners in the Wales side that reached the semi-finals of Euro 2016 in France (John Walton/PA)

It seems likely the USA game will be too soon for Allen to start in Doha, with the remaining group matches against Iran and England more realistic targets for involvement.

Ledley won his own fitness battle at Euro 2016 to feature alongside Allen, remarkably coming on as a substitute in the Slovakia opener just 35 days after breaking a bone in his leg.

“Back in 2016 they took me out when I was a doubt, but I had more preparation than Joe has had,” said Ledley, who will be in Qatar as a Wales supporter this time.

“The season had finished, so I had a little over a month to get ready. I worked so hard, I was in the best condition I ever was as a player.

“Joe is in a similar situation at the moment, unfortunately. But I’m sure when he gets his opportunity he will be ready, although we will have to leave it to the medical staff to decide whether he is OK.

“It was difficult to try and hold myself back, just as I was getting back to full fitness.

“Training with a fractured bone was quite difficult, the last thing you wanted to do was get into a tackle and someone fall on it.

“Joe’s injury is a muscle injury, so it is different. You don’t want to be overstretching in training, but once that whistle goes in a game situation, it just all floats to the back of your mind.”

Allen’s potential absence means Ethan Ampadu is set to be deployed further forward to form a midfield partnership with Aaron Ramsey.

Netherlands v Wales – UEFA Nations League – Group 4 – Stadion FeijenoordEthan Ampadu is set to play in a more advanced role for Wales in their opening World Cup game if Joe Allen is unavailable (Tim Goode/PA)

Chris Mepham would line up in central defence alongside Joe Rodon and Ben Davies, with skipper Gareth Bale, Kieffer Moore and Daniel James forming a three-man forward line.

Ledley told S4C: “That first game of the tournament is crucial. If you lose that, you are playing catch-up and you are trying to force yourselves to get the win.

“USA are not an easy team to play against, they have some fantastic individuals.

“It’s a tricky start to the group, but I don’t see why Wales can’t make it through.

“This Welsh team has been in these big occasions before – and I see a similar unity and feeling in the group to what we had in 2016. That had a massive part to play in what we achieved.”