"Nick has gone to hospital with an injury to his shoulder and it certainly looks more serious than not serious at this stage, so we are really disappointed in that," Dyche told reporters.
With captain Tom Heaton recovering from a calf injury, Burnley have just two fit goalkeepers in Lindegaard and Adam Legzdins heading into Sunday's pre-season friendly against Montpellier at Turf Moor.
They host the second leg of the Europa League tie against Aberdeen on Aug. 2.
(Reporting by Aditi Prakash in Bengaluru; Editing by Peter Rutherford)