Sunderland boss Roy Keane has revealed striker Kenwyne Jones will undergo a knee operation on Monday.
The Trinidad and Tobago forward suffered knee ligament damage on international duty against England in June.
And Keane confirmed that he will go under the knife to determine the seriousness 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 after Sunday's 1-0 friendly defeat to Ajax.
"We'll know one way or another tomorrow so I'll be saying a few prayers tonight."
Kieran Richardson missed the game with Ajax with a back injury, but Keane says he was left out merely as a precaution.
"Kieran just had a stiff back the last couple of days," Keane explained.
"There was no point risking him today. I'd be very surprised if he wasn't on the flight to Ireland with us on Wednesday."
Fans' favouriteEl-Hadji Diouf impressed against Ajax and it appears the former Liverpool man is quickly establishing himself as a firm fans' favourite amongst the Sunderland faithful.
Keane was happy with Diouf's showing and is hopeful his performance is a sign of things to come ahead of the new season.
"I think it is important for any new player to come in and leave a mark very quickly, but I was generally very pleased with his performance as I was with all the new players," added Keane.
"Obviously some fans take to certain players and hopefully he will become a favourite amongst the fans.
"As I said when I signed him (Diouf), opposition fans never particularly used to like Dioufy but our fans have taken to him and hopefully that will bode well for the rest of the season."
SigningsKeane also revealed he is still hoping to add to his squad before the close of the transfer window.
The Irishman has already brought in six new faces this summer and he admits the club are working hard to bring in more players.
"We hope (to sign more players) so we have got two weeks to play with," added Keane.
"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."