And the star wing admits he faces a race against time to face Martin Johnson's men at the Millennium Stadium in Cardiff.
"I'll be gutted to miss the game because there is no bigger game than Wales versus England," said Williams.
"I went over on my ankle tackling Jason White. I've done the ligaments in my ankle about ten times and hopefully it's not as bad as I first thought - but I just don't know.
"I've iced it up and compressed the swelling straightaway. I had also strapped up my ankle before the game because of my problems in the past. I just hope I will be available for selection."
The positive news for Williams, who scored his 45th Test try in Wales' impressive first title defence, is coach Warren Gatland has delayed naming his side by 48 hours to Thursday for the Millennium Stadium showdown.
Gatland also has injury concerns over skipper Ryan Jones, centre Gavin Henson and scrum-half Gareth Cooper who all missed the emphatic victory in the Scottish capital.
"We will re-assess the players' fitness over the next couple of days, " said Gatland.
"With such a short turnaround, we won't really start training until Thursday.
"But it's great that we are developing our strength in depth."