Young Middlesbrough forward Jonathan Franks has been ruled out for three months after being told he needs an operation on a troublesome back problem.
The 20-year-old, who made 23 league appearances for the club last season, has a herniated disc and is expected to have an operation in the next couple of weeks.
Boro manager Gordon Strachan said he would have brought Franks into the squad for the Carling Cup tie at Chesterfield on Tuesday had he been fit enough.
He told the club's official website: "I would have included Franks against Chesterfield but he is another one who is going to be out for a long time because he needs an operation on his back.
He added: "At the same time, we're waiting on (winger) Luke Williams because he got a kick in training on Monday.
"It would certainly be nice to have some wide players because Andy Halliday is injured too otherwise he'd have been in contention."