Tottenham boss Ange Postecoglou admits Rodrigo Bentancur injury is a heavy blow.
The Uruguay midfielder is expected to be out until February after a fresh setback.
Postecoglou said: "The biggest emotion you have is for him. I've only been here six months but even in that six months you see how hard they work to get back, especially him. A lot of it is a fairly lonely journey because you do the rehab on your own and you have to push yourself.
"From the moment I arrived, I think my first day I bumped into him, he was just that determined to get back. He had his own timelines in his head and he kept banging on my door about being involved. We held back because obviously with such a significant injury you want to make sure they're ready.
"He'd done everything right. He had a good international break where he got back playing for his country and he started the [Aston Villa] game so well. With all that context you're just gutted for him because of the person he is and what he's gone through, but that's unfortunately the challenges football sometimes throws up at you.
"He's still such a positive guy. I caught up with him yesterday and he's just determined to determined to crack on and get back as quickly as possible. And can't wait to get him back in because you saw his quality."