Don returned to fitness in the latter half of the last campaign but had to be a frustrated bystander in the run-in, making only fleeting appearances as a substitute.
But Glenn, full of praise for Don's opening preseason performance against Bournemouth on Tuesday and acknowledges that his presence could be even more vital next season if Trevor Sinclair moves on, and says:
"We would be short on wide men but Hutch is fully fit again and I was pleased he got two goals on Tuesday - he took them really well and the second one was a screamer.
"Don has never lost his enthusiasm and some people take a long time to get over a cruciate knee ligament injury.
"His was a nasty one and I have known players to take a year which is basically what it has done with Don.
"But it is a fresh start for Don and he is looking good."
If Trevor does go, it will be a step closer to making up the shortfall that the loss of Premiership status has caused, and Glenn adds:
"We know that we have to sell a few players before I can bring some in but it is a case of if we were to lose three for example we need to bring in five or six minimum.
"We are operating with basically 12 senior players at the moment - and to say that makes my job difficult is an understatement."
Glenn is determined to hang on to Joe Cole, however, and he adds:
"Joe has matured ever so much in the last nine months and he will continue to do that; I keep telling Joe 'no matter how good you are now, in four or five years you are going to be even better.'
"Because of his attitude and him as a person he will allow himself to improve and become an even better player than he is now.
"His all round game is getting better and his game is not just about picking the ball up and having a dribble.
"He played a lot of one touch and two touch on Tuesday and he has got his season as far as goal scoring is concerned under way because he got the last goal at Bournemouth."
Glenn is also delighted that Jermain Defoe was given a fair reaction by the fans at Bournemouth despite his transfer request at the end of the season which the club turned down.
"Rightly so; the fans saw the effort he put in on Tuesday and he did everything he could to score a goal," he says.
"He hit the woodwork a few times and had a few efforts, but we had to take him off because he got cramp which is understandable in his first run-out - and we couldn't risk him pulling a muscle when he is so important to us."