Other new players to the squad are former Warriors U20s and 2011 NZ Schools wing Ngataua Hukatai, 2014 Counties Manukau B top tryscoring wing Sione Fifita, Samoan U-20 midfielder Joe Ikenasio, and Manurewa hooker Michael Lea, while Onewhero halfback Richard Judd has been added to the squad as cover for the injured Augustine Pulu.
Fullback Jared Page will again show his wares after scoring 49 points in his two Ranfurly Shield appearances last season.
"We have retained the core of our team from last season, which is pleasing. We have also given some players the opportunity to take the next step up who have shown good form during the Counties club rugby season," said Umaga in his final project before joining the Blues for 2016.
"As this is my last season with Counties Manukau, I am keen for our team to do well for our supporters and finish on a strong note for a provincial union that will always remain special to me."
The Steelers open their campaign on August 16 in Pukekohe against Manawatu.
Counties Manukau
ITM Cup squad:
Props: Sam Aiono, Sean Bagshaw, Jarrod Firth, Pauliasi Manu, John Tu'ungafasi. Hookers: Sione Anga'aelangi, Michael Lea, Gafatasi Su'a. Locks: Mike Lawrenson, Viliame Rarasea, Sikeli Nabou, Jimmy Tupou. Loose forwards: Onosa'i Auva'a, Sam Henwood, Dan Hyatt, Jordan Taufua, Maama Vaipulu. Halfbacks: Kane Hancy, Richard Judd, Augustine Pulu. First fives: Nathan de Thierry, Piers Francis. Midfielders: Johnny Fa'auli, Joe Ikenasio, Sam Vaka, Cardiff Vaega, Sonny Bill Williams. Wings: Sione Fifita, Frank Halai, Ngataua Hukatai, Toni Pulu. Fullback: Jared Page.