Freak knee injury could keep former Preston North End defender sidelined for a long spell
and live on Freeview channel 276
Fisher hurt his knee at home and has had a series of injections over the summer to ease it.
Boro told Neil Warnock told BBC Tees Sport: "We don't actually know yet and we're crossing our fingers.
Advertisement
Hide AdAdvertisement
Hide Ad"It was an accidental thing. I think he had his legs up at home and I think someone in the family just fell on his knee and just clinked it.
"We don't know yet. He's had three injections over the last few weeks and we should know more in about a week's time.
"But we think he could be out for a while at the moment and we're just crossing our fingers that it's nothing worse."
North End sold Fisher to Boro in the January transfer window.
Advertisement
Hide AdAdvertisement
Hide AdThe 27-year-old made 119 appearances for PNE after signing from Rotherham in July 2017.
Fisher has played 12 times for Boro, one of those games against North End in March at the Riverside Stadium.
Thanks for reading. If you value what we do and are able to support us, a digital subscription is just £1 per month for the first two months. Try us today by clicking here