The Potters are already without captain Ryan Shawcross (back), Glen Johnson (knee) and Marc Wilson (knee) while Geoff Cameron has only just returned from an ankle Phil Bardsley sustained a calf problem in Wednesday night's 1-0 win over Newcastle United.
Ahead of Saturday's meeting with the Blues at Stamford Bridge, Hughes said: "We've got five fit defenders at the moment, but some of them aren't 100 per cent fit.
"We are a little bit stretched, it is fair to say, but the guys are putting their hand up and getting out there, so that's good.
"We felt if he'd been able to play in the centre-back position, maybe it would have been better for him, and obviously once Phil got injured and had to come off, then he had to get down the right-hand side and put crosses in.
"That was always going to compromise his injury, but we hope he is going to be okay."