The flanker will return to action on January 20th; two weeks before Wales's opening game against Ireland.
Wales lock Cockbain, who missed all four autumn internationals in November after receiving a twenty day ban for stamping, is backing Williams to come back fitter and stronger.
He said: "Every cloud has a silver lining and Martyn must make the most of the opportunity to rest and get himself right. He has played a lot of rugby already this year.
"I am sure he will be back involved with the RBS Six Nations, I can't imagine it without him being there. He'll probably do what I did and use the time for some good recovery and to come back stronger.
"He'll benefit from the time away; all of us are playing a lot of rugby and when you get a break, like I did in the autumn, you have to get in the gym and get all your niggles right. He'll come back flying."
Having sat out all four autumn games, Cockbain's path back into the Welsh team could come at the expense of his Ospreys team mate Ian Evans, who looks set to miss the rest of the season with a dislocated shoulder.
The twenty-two year old is struggling to be fit for next year's Rugby World Cup in September 2007 and faces reconstruction surgery which would keep him out until June 2007.
Cockbain wished his teammate a speedy recovery and added: "It isn't great news for him or for the Ospreys because we are going well in the Heineken Cup and Ian is an important part of our team. Fingers crossed he'll be back for the Rugby World Cup."