Moeen tested positive for Covid-19 on arrival into Sri Lanka and was told to isolate for 10 days, with England later confirming he would play no part in the first Test in Galle from Thursday.
The 33-year-old is feeling better but his quarantine period is now being extended with the Sri Lankan government being extremely cautious with regards to coronavirus cases.
The England and Wales Cricket Board are understood to be sympathetic to the decision and expect Moeen to be allowed out of his private accommodation around the weekend.
Speaking earlier in the week, England head coach Chris Silverwood said: "Moeen is in good spirits - as good as he can be. He is feeling okay in himself and from a physical point of view.
"We are all looking forward to having Mo back in the camp with us and seeing him. He is getting a lot of support - I know the lads are constantly messaging him and checking in on him, as are our medical team."
Due to the off-spinner's time in isolation, the ECB does not expect him to be match sharp in time for the second Test, also in Galle, from Friday, January 22 but will make a call on him in due course.
Dom Bess and Jack Leach are set to play as England's frontline spinners against Sri Lanka, although Mason Crane, Matt Parkinson and Amar Virdi are also options having travelled with the squad as official reserves.
England all-rounder Chris Woakes spent a week in isolation after being deemed a close contact of Moeen, with the pair having shared transport to the airport before flying out to Sri Lanka.
On Moeen, Woakes said: "Poor bloke, he's obviously had it a little bit tough having been in isolation pretty much since we got here. Everyone's making sure he's okay but I can only imagine what he's going through.
"I did seven days and he's ended up doing a lot more than that. He had some symptoms which I think he's over now, which is good, but you don't wish this illness on anyone.
"I was in contact with him all last week when I was in isolation - we were both talking about what we were up to. I know the guys have played a lot of PlayStation with him as well. talking to him through the headsets.
"It's tricky in these sort of times when you are having to lock yourself away in a room, I have certainly not gone through that before so it is unprecedented times.
"Thankfully he's recovering pretty well. I think he will be excited to get out and be amongst the group again."
Watch the first Test between Sri Lanka and England, live on Sky Sports Cricket from 4am on Thursday.