|Honours:||Maori All Blacks|
|Date of birth:||4 September 1988|
|Weight:||92kg (14st 7lb)|
The much-travelled centre made over 40 appearances during his two-year spell at Worcester following spells in his native New Zealand and France.
He won the Junior World Championship with New Zealand U20s in 2008 and has gone on to feature seven times for the Maori All Blacks.
Willison spent five seasons with Waikato Chiefs before one-season stint with the Blues and two seasons at Grenoble.
The centre made a huge impact in his first season at the Club, featuring regularly in the first team, with 16 appearances.