The 33-year-old has not played since suffering a knee injury in the Blues' 24-9 victory over the Stormers on March 30. He underwent surgery two weeks later.
His contract with New Zealand Rugby expires after the Rugby World Cup in Japan later this year and while local media reported he could head abroad to wind down his career Williams was giving little away on Thursday.
"You never say never," he told reporters in Auckland when asked if it was his last training session with the Blues. "I'm just really focused on this week and trying to get a win with the boys and get some rugby.
"The body's good, I'm ready to go."
The Blues season will end on Saturday after they failed to secure a spot in the playoffs for an eighth successive year.
Should he get through the match unscathed Williams is almost certain to make Steve Hansen's All Blacks squad for the shortened Rugby Championship that starts next month.
Williams has helped the All Blacks win the last two World Cups and while he has been beset by injury since the 2015 tournament in England Hansen has said he only needs to prove his fitness to be in contention for a berth in Japan.
There was further good news for Hansen with hooker Dane Coles being named to start his first game since mid-March for the Hurricanes.
The 32-year-old returned to the field for the Hurricanes off the bench over the last two weeks in South Africa, scoring two tries last week in the Hurricanes' 37-17 win over the Lions in Johannesburg.
(Reporting by Greg Stutchbury; Editing by Peter Rutherford)
