Parker has yet to play this season due to an Achilles injury and although Villas-Boas is encouraged by the 32-year-old's recent progress, he is uncertain how soon he will be ready to return.
"It's difficult for him as he still feels pain and is still disturbed in his recovery," said Villas-Boas, quoted in several national newspapers.
"It prevents him from being on the pitch but he has been in the gym with the medical department.
"It will take two or three weeks - but we could be looking at Christmas. Hopefully it will be less.
"It is still within the limits of what we expected.
"He is making good progress and there has been less pain."
Source: PA
Source: PA