The Wellington-based national body is yet to confirm the New Zealand Herald's weekend revelation that Williams will shun the year-to-year contracts he has signed most of his career for a three-season stint with NZR.
But Umaga's moves - including a quick trans-Tasman visit to meet Williams' controversial agent Khoder Nasser, rather gives the game away.
There could be an announcement on Williams' New Zealand future, including which Super Rugby franchise he will play for, as early as tomorrow or Thursday.
The Blues and Chiefs are locked into a battle for his services.
But the Auckland-based franchise is playing as many cards as it can as it seeks to secure a signature that could help turn the Blues around.
Umaga's friendship with Williams is seen as a potential persuader. The former All Blacks captain was at Toulon when Williams first launched his rugby career after sensationally quitting NRL club the Bulldogs for French rugby.
The pair were briefly reunited at Counties when Williams had a stint in the National Provincial Championship and Umaga was on his coaching apprenticeship.
Umaga recently lamented that the Blues were still struggling to prove to top players that they are a franchise with a future.
Williams signing on would go a long way towards ending that perception.
But the Chiefs will be backing their culture to sway Williams.
He has already won a Super Rugby title there under Dave Rennie and enjoyed his time in Hamilton far more than his first Super Rugby stint with the Crusaders.
Rennie lauded Williams for his professionalism, saying he was a player who inspired strong training and commitment among team-mates by setting an example.
It is just the attitude the Blues can do with.
While Umaga was in Sydney, he also dropped into NSW's State of Origin training.
He has a relationship with NSW assistant coach and Samoan coach Matt Parrish who visited the Blues last year.