Already out since July, our Irish international star will now be on the sidelines for up to four months after undergoing surgery in America on Wednesday.
The problem - an aching pain from the joint of the knee - surfaced midway through pre-season and a six-week spell of rest failed to cure it.
Full-back Stephen now faces the long haul back and boss Glenn confirmed: "Stephen's had surgery and will be out for three to four months.
"The problem has been identified. Rest was the first port of call but that unfortunately didn't give us the player back.
"The good thing is that the surgeon in America, I think it was the same one Jamie Redknapp and Ronaldo went to, has identified what the problem is so we can get him right.
"But we've been told it's four months out which is a major blow for us."
It's been a defensive nightmare for Glenn. He has already lost Gary Doherty (broken leg) and Goran Bunjevcevic (fractured cheekbone) for what look like lengthy spells this season and now Steve, but at least long-termers Ben Thatcher (out since last November) and Anthony Gardner (out since May) are on the way back after featuring in behind-closed-doors friendlies.
Glenn Hoddle has described Stephen Carr's prolonged absence after knee surgery as 'a major blow'.