Lars Hirschfeld, Gary Doherty, Stephane Dalmat, Mbulelo Mabizela, Helder Postiga and Bobby Zamora are all involved at Portman Road and that means the likes of Lee Barnard, Mark Hughes and Rob Burch are back on the bench.
"Unfortunately for some of the younger ones, because of players needing a game, they are going to miss out," Colin explained.
"The squad is bigger, there are a lot of players fit and they need a game.
"It's a case this season for the younger lads, as I said to them, that every time they play they have to see is as an opportunity.
"They might have limited chances so they have to make the most of every opportunity when they do play, whether it's against a strong Arsenal side or a young West Ham side.
"They must do something every time they play that makes an impression on the management."
Meanwhile, Colin is looking forward to the FA Premier Reserve League clash at Portman Road - recent home of an England international.
"Ipswich are good side and very capable of playing good football," added Colin.
"It's good for the senior players because it's a great game, a nice surface and they have to go an do themselves justice because there are boys underneath them who want to play."
A look at tonight's reserve team line-up at Ipswich underlines Colin Calderwood's warning to our youngsters they they have to grab every chance with both hands this season.