Richard Chaplow is set for an extended spell on the sidelines after the Doncaster Rovers midfielder suffered an injury setback.
The 30-year-old former Southampton midfielder has not played for Rovers since October 24 in a 4-0 loss at Peterborough.
He has had to sit in the stands as new manager Darren Ferguson engineered three successive wins, two in the league, to help Rovers climb away from trouble in League One.
But Chaplow could miss the next month after a new scan revealed a tear to his Achilles.
“Richard Chaplow has had a bit of a setback so he’ll be out longer (than anticipated),” said Ferguson.
“We sent him for another scan to get him an injection, but there is a bit of a tear in his Achilles that we didn’t pick up straight away. That could be another three or four weeks.
“It’s a bit of a disappointment for the boy.”
Chaplow is joined on the injured list for tomorrow’s visit of Rochdale by defender Gary MacKenzie.
Ferguson added: “Curtis Main picked up a back injury so he could be doubtful. Paul Keegan did a bit of running so we’ll see how he is but he won’t be available on Saturday. Hopefully he will next week.
“We got a bit of work into them. Tuesday was a demanding day physically. It was good. (Yesterday) they were quite good,” said Ferguson.
“It’s been about building up to Saturday. We start Monday, looking at specific things we want to do against Rochdale and specific things we’ve seen in their videos and games we can work on.
“Thursday is the day where we get the more specific messages over to the players.
“Friday, I always like to be a relaxed day, let the lads be short and sharp and we’ll do the video stuff.”
Sheffield United have sent defender Terry Kennedy out on loan to gain regular first-team football.
The 21-year-old has joined League Two side Cambridge United on loan until January 3.
The Academy graduate – who made his Blades debut in 2011 – has made just three appearances this season.
Kennedy last night Tweeted: “New experience for me. Hopefully show Cambridge what I can do and help the club climb the league. Can’t wait.”
The defender could make his U’s debut against Accrington Stanley at the Abbey Stadium tomorrow.