Stanley, the nephew of former All Blacks midfielder Joe Stanley, is a former IRB world junior player of the year nominee and a former New Zealand under-20 representative.
He is also the younger brother of former All Black second-five Benson Stanley.
Having made his debut for the Blues in 2009, the 95kg centre-come-wing has gone on to be capped 26 times at Super Rugby level.
He played six times for the Blues and 20 for the Force across his two seasons with each team.
Parkinson also confirmed the hunt was on to secure a Super Rugby prop for next year's ITM Cup team.
"There is room in next year's budget to bring in a Super Rugby prop, because if your front row isn't upright it's pretty hard for your forward pack to operate," said Parkinson.