It's a blow for us - because for me Max is one of the best full-backs in the league - that's how highly I rate him.Garry Monk.
The influential French full-back limped off during last weekend's away defeat at Hull City.
"Max Colin will be out," said the Blues boss.
"He came off with a hamstring at the weekend.
"It's a blow for us - because for me Max is one of the best full-backs in the league - that's how highly I rate him.
"Time-frame we're looking for him to return around the international break.
"But it is what it is.
"We haven't got a big squad but what we have is people ready to come in and to give everything they've got."
In Colin's absence, Wes Harding is expected to step in at right back.
But Monk has no qualms about the 22-year-old's ability to handle the big occasion.
"I have got no fears about any of the players, they have all shown they can contribute and they are all ready to go," he said.
"This is just part of it, you have to deal with it. It probably affects our squad more than quite a lot of others when we do have injuries.
"We start to delve very quickly, this weekend will be our 18 fully fit available players so it's quite easy in terms of selection but not so good for the depth of the squad. We know that.
"The lads have got on with that brilliantly."
Meanwhile, the only other two players that were on the injured list - Marc Roberts and Charlie Lakin have both returned to full training, although will need to regain match fitness before being considered for selection.
"They started training yesterday, they are not going to be fit for this game but they are back in training which is a boost for us," added Monk.
"It will probably take them until the international break to be anywhere near the fitness that we need."