Roberts does not believe he will be available for Sunday's visit of former club Wigan in the Premier League. The 31-year-old was sidelined by a stress fracture of his foot a fortnight ago and was expected to be out for at least three weeks.

"The injury is a strange one because if you have a broken bone then you know exactly how long you are going to be out for," said Roberts.

"However, with a stress fracture you can't be sure as it isn't as straightforward so you have to be careful in case it happens again and you have a setback.

"It is doubtful I will be ready for next week."