Nick Pope has undergone an operation for a dislocated shoulder leading Burnley to apply for special UEFA dispensation to sign a new goalkeeper.
England keeper Pope suffered the injury in the first leg of Burnley's Europa League qualifier against Aberdeen and, with Tom Heaton also out, manager Sean Dyche's options are limited for the return fixture.
Anders Lindegaard came on as a substitute at Pittodrie, but the Clarets are not putting a timescale on Pope's return.
"He's had the op," Dyche said. "So far it's pleasing news in the sense that the specialist was happy."
Burnley have been linked with a loan swoop for Southampton's Fraser Forster, but they require UEFA's permission to register a player for the second leg at Turf Moor, with the tie level at 1-1.
While Dyche revealed the club have made an application, he is keen not to rush into any signing.
"We need to get the right ones in, to bring people in to affect the group," he said.