Sunderland striker Kenwyne Jones is set to miss the start of the season after undergoing knee surgery tomorrow.
The 23-year-old striker suffered knee ligament damage in Trinidad and Tobago's friendly against England in June.
After today's 1-0 loss to Ajax, Black Cats boss Roy Keane said the operation will determine the extent of the injury.
"Kenwyne's going in tomorrow for an operation and we will know in 24 hours of the exact damage so fingers crossed," Keane said.
"We'll know one way or another tomorrow so I'll be saying a few prayers tonight."
Kieron Richardson also missed the friendly against the Dutch giants with a back injury as a precaution.
Keane has made six summer signings, in a bid to improve Sunderland's 15th-placed finish last season, including El Hadji Diouf and Teemu Tainio.
The ex-Manchester United skipper added he is working hard to bring more new faces to the Stadium of Light.
"We hope (to sign more players) so we have got two weeks to play with," Keane said.
"We are working extremely hard and of course we keep saying it takes time but hopefully in next few weeks something will happen.
"I am generally pleased with the way pre-season has gone and hopefully we didn't pick up any injuries."© Adfero Ltd