Downing has been struggling with a slight knee injury ever since the international break as Allardyce prepares his side to face Newcastle United.
West Ham United midfielder has returned to training for this weekend's clash against Newcastle United this weekend after struggling with a knee injury.
Downing returned from international duty with England with a slight knee injury and has been nursing it ever since.
Manager Sam Allardyce also confirmed that Cheik Kouyate has also returned to training, and described this weekend's opponents as the second most difficult side in the country given their recent good form, with Alan Pardew's side winning five games on the bounce.
He told reporters: "We've got to try and beat the most difficult team to beat in the Premier League at the moment, apart from Chelsea, on Saturday.
"Stewart Downing is training today and Cheik Kouyate is too. The rest have got a chance, but a slimmer one.
"We've lost Winston Reid to a suspension too and we've got to manage the situation by getting a result against Newcastle."
Mark Noble, Enner Valencia, Diafra Sakho and Alex Song all remain doubts for this weekend's game through injury as Allardyce said he wants his side to put a 'mini-blip' behind them after a positive start to the season.
The Hammers were in the Champions League places not so long ago but have recently dropped points against Stoke City, Aston Villa and Everton.
The Hammers boss added: "The next run of games will be hugely important for our season. When the international breaks are out of the way, dealing with the games coming thick and fast in the run up to Christmas is a big test."