Sheldrake suffered his injury during Keighley’s defeat against Leigh and could be out for up to a month.
Coach Barry Eaton said: “We went really well for large parts of the game against Leigh. They were clinical when they got their opportunities and they also scrambled really well when we had our own opportunities.
“It could have been as close as can be, but they took their chances and we squandered some of ours.”
He added: “There is not much that’s new that we can now give the players. We’ve covered everything we can in terms of training and game preparation.
“The only thing we can give them now is some more structure and some knowledge of the opposition. It’s then up to the players to go out and carry out our game plan.
“Featherstone are the most consistent side in the league and that’s a challenge we’re going to have to face head on. We’ll take positives from giving the second placed team a real run for their money.”
Rovers also have their own problems, with winger Tommy Saxton also missing for a month after suffering an ankle injury against Widnes.