Stoke City duo Dave Kitson and Ryan Shawcross will undergo scans to determine the extent of injuries suffered against West Bromwich Albion.
Kitson lasted just 10 minutes of Stoke's 1-0 win last weekend after picking up a knee injury and the striker was replaced by Richard Cresswell.
And Shawcross was substituted towards the final stages at the Britannia Stadium after the centre-half hurt his back.
Both players are due to visit a specialist on Tuesday, with Potters boss Tony Pulis admitting he is still to discover the severity of the injuries.
"The injuries are all a bit of a mystery in both cases, but hopefully the specialist can shed some light on just what is going on," Pulis told The Sentinel.
"It's obviously a concern for us and for the players when you are in the dark, but we'll see what today brings before deciding our next step.
"Either way, both Dave and Ryan could be struggling for Saturday."
However, Stoke skipper Andy Griffin is set to face Hull this weekend, despite breaking his hand against the Baggies.
Pulis added: "We'll get a plaster-cast sorted for his hand and that should mean he is all right to carry on playing.
"You know he's the kind who wants to be out there at all times."