Lee Cattermole and Jan Kirchhoff will not be fit to face Middlesbrough on Sunday, David Moyes has revealed.
Cattermole will undergo surgery on a hernia and is expected to miss between four and six weeks of the campaign, with Kirchhoff remaining out due to a hamstring injury.
Moyes also confirmed that Lamine Kone (back) and Billy Jones (hip) will also be unavailable, and there are also doubts over fitness of Fabio Borini (toe).
"Jan had an injection to see if they could cure a bit of neuro pain leading into his hamstring - he is on the mend but we need to get him match fit.
"Lee Cattermole has had a double hernia and as you know Seb Larsson has had an operation that will keep him out for up to six months.”
He added: "We have a few injuries, Billy Jones' hip problem, so it has just kept us a little bit low.
"We have a doubt over Borini with a toe injury."