Cougars player-coach Paul March is facing the grim prospect of being without captain James Feather for several weeks due to a groin injury.
The long-serving hooker was struck down during last Sunday’s 36-14 opening-day victory against Whitehaven.
He was due to undergo a scan this week to assess the seriousness of the injury but March admitted the early prognosis was not good.
The Cougars boss said: “We’ve probably lost 'Buster' for a few weeks.
“He has picked up a groin injury and it’s a pretty bad one.
“It’s a big loss to be without our captain but, at the same time, it’s somebody else’s gain.”
March played alongside new signing Paul Handforth in the halves during the resounding win over Whitehaven.
But, with Danny Jones set to be available after illness for Sunday’s trip to Doncaster, March could deputise for Feather at hooker.
The Keighley chief, who was among the try-scorers against Whitehaven, added: “Danny Jones was ill at the weekend and there was a bit of a flu bug going round the camp so I left him out.
“He should be back this weekend and I can go into nine, Jack Lee can play there and we’ve got Sean Kelly and Ben Stead too, so we’ve got options in that position.”
The loss of Feather could be offset by the return of loose forward Ash Lindsay as he approaches full fitness.
The close-season signing from Batley has been sidelined since partially dislocating a shoulder in January and March is undecided on whether to throw him in against Doncaster.
He said: “Ash could be back but I might leave him another week because we’re running pretty much at full strength with the exception of Buster’s injury. The longer we leave it, the stronger that Ash’s shoulder is going to be after the dislocation.
“Lewis Graham will be back in contention this week after his broken hand and Jode Sheriffe and Ryan Patchett will come back into contention as well.
“They were supposed to play at the weekend but failed to turn up for training and lost their spot. Their challenge now is to win it back.”
Cougars are in buoyant mood as they seek to overcome a Doncaster side who claimed an impressive 22-12 victory at Workington in their Championship opener.
March said: “The three points were crucial against Whitehaven and we want nine points from our first three games.
“That’s what the lads have sat down and targeted, so hopefully we can achieve our goals.
“We’re not focused on the opposition because it’s about what we do. If we do that then I’m sure we’ll come away with the points.”
Like Cougars, Doncaster have an ex-Super League man as their player-coach in Paul Cooke who, like March, has ambitions to ply his trade at the highest level.
March said: “Paul’s a bit like me, he’s getting on a bit and can probably pick and choose his games, but he still pulls the strings.
“I like to think I can go on to bigger things like Super League but at the moment everything is focused on getting Keighley into this second tier (of the new structure).
“You never know, in a couple of years’ time, I might be a Super League coach with Keighley Cougars.”
Elliot Cosgrove and Josh Lynam were named in the first Kingstone Press Championship Player of the Week for 2014 for their outstanding displays against Whitehaven.