The boss feels that a straight four-man midfield negates Gus's attacking instincts and that the livewire midfielder is loving the freedom currently afforded to him.
"When I bought him I felt that Gus had scored goals in probably two systems I watched him play in at Chelsea and Real Zaragoza that really didn't suit him," reasoned Glenn.
"He was always playing wide of a four across. My vision was to play him off the front or in a three in midfield - whether it was 4-3-3 or with the wing-backs.
"It allows him to get into the box, it allows him to go from either side. He hasn't just got to rely on crosses from the right hand side if he's playing left of a four which he did mainly at Chelsea.
"So we've freed him up and he's loving it, lapping it up."
Cardiff here we come! Travel and visitor info
Apparently, Gus is more than a bit lively at the moment in his preparations for Cardiff on Sunday, and Glenn could not resist having a little joke aimed in his direction.
"He's like a little kid in that dressing room now, getting his tickets organised for the final with people flying over from Uruguay. It'll be a shame when I tell him he's not playing!" laughed the boss.
Sunday's FA Cup win over Tranmere saw Glenn explore another midfield combination option, with Simon Davies joining Gus and Tim Sherwood in the centre.
"That three in the midfield was the first time we've played that, with Gus and Simon playing off and around Tim. I was pleased with that, I thought Gus and Simon played off each other really well.
"We asked them not to get caught in the same position when we were on the ball and that worked very well.
"Simon's learning more and more and more, and is progressing very quickly as a player with the experience around him. He can only get better and better."
Glenn explained on Sunday that getting the best out of Gus Poyet is all about employing the right system of play.