The shot stopper has been in outstanding form since the start of the campaign, earning the club’s Player of the Month award in September.
Henderson also got his first start for England during the October international break.
Ahead of tonight's clash with Nottingham Forest, Glasner admitted: “I was impressed from the first day when I arrived, and also not just with Dean from the goalkeepers’ group: at that time with Sam (Johnstone) and with Remi (Matthews) and Joe (Whitworth), and Dean Kiely who leads the group.
“They’re very ambitious, very hard-working, always supporting each other. Dean accepted his role when I arrived – we said: ‘okay, Sam was the keeper at that time, so I don't want to change it’, and he (Henderson) was always working.
“Then, he was here for the team when the team needed him, and from that moment he showed great performances. Also I remember the first win we had after the period at Liverpool at Anfield, and he could keep this and he is still ambitious, hard-working, positive, and I think he got the start for England that he deserved.”