Sunderland boss Gus Poyet says defender Anthony Reveillere is facing three to four weeks on the sidelines.
Reveillere, 35, injured a muscle between his Achilles and calf during the warm-up for Sunderland's derby clash against Newcastle on Sunday.
Poyet said the club had initially feared the problem was more serious, but the former France international will still be out for up to a month.
"It's a muscle injury," Poyet told a news conference. "We thought it was more because of the way it was translated between languages, but then after the scan they checked and, although it wasn't a typical muscle scare, it's going to be between three and four weeks.
"The way he did it made us worry."
With John O'Shea having been pressed into service at left-back in the win against Newcastle, Billy Jones is set to take that position against Hull on Boxing Day after over two months out with injury.
However, Poyet said Patrick van Aanholt is also close to a return to fitness.
"Patrick is ahead of schedule and he is going to be training with us at the beginning of January," he added. "If you see him running you would think he is ready to play but he has not had any contact yet. That's a process, the first push, the first knock.
"We thought he needed two weeks of that; now we'll see. Can we afford to give Patrick two weeks? It will depend on the games and it will depend on Billy."