MK Dons defender Danny Swailes will undergo surgery in a bid to cure a troublesome Achilles injury.
Swailes has made just one appearance for the Dons so far this season due to the injury, despite a number of treatments this summer attempting to correct it.
Dons boss Roberto Di Matteo was able to bring in experienced Spanish defender Miguel Angel Llera as cover before Monday's transfer deadline, but admits the loss of Swailes is a blow.
He said: "It's still an Achilles problem for Danny and he'll have an operation on that this week.
"It's another big blow for us; he was a big player for this team last season. Things don't seem to be getting easier for us as we go along.
"Miguel is 6ft 3in tall, he's got a bit of experience and he's good on the ball so hopefully he'll be a good asset for us."