With seventh place now guaranteeing a place in the competition due to Chelsea and Arsenal's participation in the FA cup final, there has been renewed comment regarding the pros and cons of using the competition to get a place in the UEFA cup.
But Glenn is insistent that he has made the right decision, and says:
"I am comfortable answering that; it is not a problem, but I maintain what other clubs who haven't entered do.
"Tottenham haven't entered it, nor has Alan Curbishley at Charlton nor Steve McClaren at Middlesbrough, just to name a few.
"At the moment, squad wise we are not strong enough, there is not enough depth, and I believe we are asking for trouble bringing the players back in June and trying to get them up to speed and fitness quicker than you would normally ask them.
"The preseason is a very important time to bring your players back to full fitness and you want to do that gradually rather than rushing them back, and with such a small first team squad we are asking for serious trouble."
He stresses that other years he might take a different view and adds:
"We like the competition; we had a terrific experience a few years ago when we had a much stronger and heavier squad, but although we started the season well after the InterToto, after Christmas I felt that we suffered a bit of a burn out and a dive in our fortunes.
"With a small squad, 38 Premiership games plus the cup games is plenty.
"Being in the Premiership is the most important thing; just look at the problems European football has caused for Ipswich.
"I do feel that being in the UEFA Cup after a first, great season in the Premiership, has caused them problems now.
"Hopefully they will get out of trouble but things are looking grim for them, and I don't believe being in the UEFA Cup has helped them at all.
"My first priorities and loyalty have got to be that we do well in the Premiership, and maybe the InterToto or UEFA Cup will come in seasons to come when we are healthier and stronger in terms of strength in depth - it's as simple as that.
"We could have up to four players away at the World Cup as well, and when it finishes these players will need at least four weeks' rest, and you couldn't expect to be bringing players of that quality back into the InterToto two weeks after the World Cup."