The 33-year-old could return for the Blues against the Reds at Suncorp Stadium next Friday and will make the All Blacks Rugby Championship and World Cup squads should he remain fit, but while he can still be a devastating attacker and defender, his playing days appear numbered as almost 15 years at the top level of league and rugby take their toll on his body. Last year he played only six games for the Blues.
In February, Williams hinted to the Herald that this could be his final season with the Blues."It could be, bro, it could be," he said, before suggesting that he was experienced enough to know that plans could change quickly in rugby.
The Blues will miss both Williams and Nonu for their work ethic as much as anything. Both men are dedicated to their craft and put in long hours in the gym and on the field in order to perfect it.
MacDonald will likely be in the market for replacements to back up TJ Faiane and Levi Aumua, with Tanielu Tele'a currently used on the right wing, able to play in the midfield.
One player definitely leaving is lock Scott Scrafton, who has signed with the Hurricanes. Scrafton has been a good performer for the Blues over the last three years and recently returned from a serious knee injury.
The Blues are well off for locks, with Patrick Tuipulotu, Gerard Cowley-Tuioti and Josh Goodhue three specialists and loose forward Tom Robinson able to play there too.
The concession of a late converted try to the Bulls on Friday which allowed the visitors to draw the match has all but shut the door on the Blues' playoffs chances.
In order to prgoress they need a minimum of wins against the Reds and then the Hurricanes in Wellington but even unlikely bonus point victories probably won't be enough.
"I've got a really good, clear idea of where we have to go to be successful," MacDonald said as he briefly turned his attention to next season. "I know where my focus areas are going to be when we come together and I know what my focus areas are for recruitment and retention.
"You feel like you're taking a step forward then you go on the park and you're taking three or four but the next day you're taking three back," he said of this season's challenges.
"When we get our mindset right around how we want to play the game, and the right people to do that, that's when we're really going to see some progress."