Wales manager Chris Coleman has major injury problems for their qualifiers against Macedonia and Belgium, and has already been forced to call up nine replacements.
Williams is the latest doubt, as he is troubled by an ankle ligament problem.
"I want to see the doctor and physios in the next couple of days and see where we are at," he told Sky Sports News.
"But everyone knows me I always try and play though the injury or as many games as I can, so if there is a chance I will definitely play."
Williams admits that his Swansea manager Michael Laudrup is keen for him to sit out the games.
"He knows me as well and he said that he feels I need a rest but if I can play I will, if I can't then I can't," he said - insisting that every international game is important.
"Every game, especially international games for Wales, you always have that feeling that it is a massive for the country.
"They are two massive games, as always, and we don't want to finish on a downer."
Wales' two remaining World Cup qualifiers are live on Sky Sports 3. Coverage of Friday's game against Macedonia begins at 7.30pm, and we're on air at 7.55pm on Tuesday ahead of the Belgium game.