Glenn hinted that, in the middle of a tough run of games, it might be time to 'use the squad' against Burnley tonight.
The boss agreed that Sunday's clash with Chelsea was a real high energy encounter and, with a long trip to Sunderland looming at the weekend, he might consider tinkering with his line-up.
Some changes might be forced, with Dean Richards, Jamie Redknapp and Robbie Keane struggling, but Glenn insists he feels the Burnley tie is as important as any Premiership match to him and it is one he desperately wants to win
"We've got a few injury scares and, with Sunderland being a big game as well and with maybe a bit of fatigue coming into the camp, it could be the time to use the squad," reported Glenn.
"I can assure you, whatever team we put out, we are not taking this anywhere near lightly.
"In actual fact, this is just as big as any Premiership game for us. We've got to get through and try and get into Europe that was as well."
Glenn explained that he is not pondering wholesale changes and the trip to Turf Moor is unlikely to signal a return to action for Ledley King, Darren Anderton or Stephen Clemence. It is simply as case of keeping the starting X1 as close to optmimum form and fitness as possible.
"We've got players coming back who are not quite fully fit and I don't know whether they would be up for a real cup tie.
"This is a real balancing act that I've got to work on going into this game. It's getting that balance right because we want to win the game."