Rotherham United will be without Sunderland loanee Will Grigg for "a long period of time" according to Millers' boss Paul Warne.
The Black Cats loanee has started the past four league games for the league leaders, but was injured in their 1-0 win over AFC Wimbledon.
Grigg has been a mainstay in Warne's side since making the move to Yorkshire in the summer, with Warne claiming his injury is a "big blow" to the title challengers.
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He said: "Griggy coming off injured is a big blow. I think he is the glue to the team really.
"His link-up play is really good and he works well with Smudge (Rotherham forward Michael Smith).
"Unfortunately, he's going to be out for a long period of time, so that isn't good news."
Grigg's struggles on Wearside are well documented, but he's been a key part in Rotherham's side this season.
The Millers boss has refused to put a timeframe on his potential return.
Warne added: "I don't really like to put a timeframe on Griggy's because the physios told me, but we think he might be about eight weeks.
"His is a severe hammy. There was obviously nobody near him when he did it. He ran and put the cross in for a chance that Smudge should definitely have taken.
"It's a massive blow. Griggy has got back to looking really sharp and his offside goal was very harsh as well.
"He'll be out for a period. As I always say, it's 'next man up' but I do say that with a heavy heart because I do think we're going to miss him."