Simon Davies and Darren Anderton were withdrawn with knocks in Sunday's 2-0 friendly defeat against PSV Eindhoven.
Ledley King (ankle), Dean Richards (Achilles), Kazuyuki Toda (calf), goalkeepers Lars Hirschfeld (hamstring) and Neil Sullivan (shoulder), Jonathan Blondel (broken finger) and Bobby Zamora (groin) were all missing against PSV.
The good news is that Dean should start training again on Monday and Glenn expects Bobby Zamora to be fit for the visit of Sporting Lisbon next Sunday.
"We've further problems with Simon Davies and Darren Anderton, who had to come off at half-time," said Glenn. "It is a problem as well, Kazu is also out and we're stretched.
"We've also two centre-backs missing, so we're only really functioning at 40 per cent.
"It's difficult and you are worrying because in two weeks time it's the start of the season but we're going to have to get on with it.
"Hopefully Darren and Simon won't be out for too long and Bobby Zamora should be okay for next weekend."
Glenn Hoddle admits he's concerned with the injuries mounting up as the start of the Premiership draws ever nearer.