The 22-year-old made his All Blacks debut last year when he came off the bench against Australia in the first Bledisloe Cup test.
He played 15 games for Auckland in the last three NPC seasons after making his provincial debut in 2019 against his new side Counties Manakau.
Sotutu, whose father Waisake played for Counties Manukau while still at high school, links up with Blues teammates, Dalton Papali'i and Nepo Laulala at the Steelers.
