The towering prop and second-rower, who went on to play for the Sydney Roosters, North Queensland Cowboys, Newcastle Knights and Manly Sea Eagles, as well as the Hull Kingston Rovers and Catalan Dragons following his eight-year, 148 game stint with the Bulldogs between 2000 and 2007, was one of the most loved figures in the NRL.
And now, he is back.
Mason was pictured helping at training for the Canterbury Bulldogs on Monday, and it would appear the man they call "Big Willie" is on the coaching staff in some capacity at the club.
— Canterbury-Bankstown Bulldogs (@NRL_Bulldogs) November 15, 2021
It's unclear exactly what Mason's role is at the Bulldogs, however, being pictured in official club gear means it could be safely assumed he has at the very least moved into a consultancy or specialist role for the forwards.
During a glittering career, the Auckland-born forward played a staggering 310 games in both the NRL and English Super League, while also playing 13 matches for the New South Wales Blues, 24 for Australia and three for Tonga.
The Bulldogs' coaching staff is being built by head coach Trent Barrett, who goes into his second year with the club desperate to turn around a horrid 2021, and Phil Gould, who has recently come on board as the general manager of football.
Gould is known to be a big fan of Barrett from their time together at the Penrith Panthers, and while the club will be quietly optimistic of a turnaround in 2022 following ten high-profile signings - including Josh Addo-Carr, Matt Burton, Matt Dufty and Tevita Pangai Junior - they will have 2021 ringing in their ear as they attempt to build both on and off the field ahead of Round 1 in March.