Marty McKenzie has beaten younger brother Damien for to the Chiefs’ No.10 jersey following All Black Aaron Cruden’s Super Rugby season-ending injury.
Marty, 22, will start against the bottom-of-the-table Western Force in Hamilton on Friday night, while Damien will be on the bench.
The younger McKenzie, who turned 20 this week, has impressed in his rookie Super Rugby season, operating mostly at fullback.
But he makes way for his sibling, who helped guide Taranaki to the New Zealand national provincial title last year.
Cruden faces at least six months on the sidelines after rupturing the anterior cruciate ligament in his left knee in the 26-9 win over the Crusaders last Friday.
He had been expected to sit out the Force match as part of the rest programme for All Blacks in Super Rugby in the lead-up to the World Cup, a tournament he is now set to miss.
Coach Dave Rennie has made three other changes in personnel to his starting 15.
Skipper Liam Messam gets a break under the All Blacks agreement and has been replaced by Johan Bardoul at blindside flanker.
Siate Tokolahi comes in at tighthead prop for Ben Tameifuna, who drops to the bench.
In a backline reshuffle, Bryce Heem returns at right wing, with Tim Nanai-Williams moving to the left in place of James Lowe.
The Chiefs’ win over the Crusaders kept them second in the New Zealand conference, but they are now just one point behind the competition’s overall leaders, the Hurricanes.
The Force are coming off a 13-6 home defeat against the Stormers – their eighth loss in a row after a season-opening win over the Waratahs.
Chiefs: Tom Marshall, Bryce Heem, Charlie Ngatai, Sonny Bill Williams, Tim Nanai-Williams, Marty McKenzie, Brad Weber, Michael Leitch, Sam Cane, Johan Bardoul, Brodie Retallick, Matt Symons (capt), Siate Tokolahi, Hika Elliot, Mitchell Graham. Reserves: Quentin MacDonald, Pauliasi Manu, Ben Tameifuna, Michael Fitzgerald, Liam Squire, Augustine Pulu, Damien McKenzie, Andrew Horrell.