Sunderland forward Fabio Borini has been ruled out for three months with a groin injury.
The Italian was replaced midway through the second-half of Saturday's 1-1 draw at Southampton after tearing a ligament in his groin.
Borini, who started two of Sunderland's first three Premier League matches this season under new manager David Moyes, is unlikely to feature again until December.
His absence also leaves Jermain Defoe and Duncan Watmore as Sunderland's only fit, recognised strikers after Moyes failed to add to his forward line on Deadline Day, missing out on a deal for Norwich's Steven Naismith.
Moyes told the Sunderland Echo: "Borini, we expect to be out for three months, that is a rough guide. There is a chance it could be a bit quicker.
"We are being told it is three months though, an adductor that came off the bone."
Sky sources understand Sunderland remain on the lookout for reinforcements, despite the end of the summer transfer window, and are weighing up potential moves for free agents.
Meanwhile, Sunderland will make an enquiry to FIFA to see if they can still sign goalkeeper Mika from Boavista.
Sunderland have insisted that all their paperwork was lodged before the deadline and that the deal was held up by the Portuguese club.