Brodie Retallick has been ruled out for up to four weeks with a left shoulder injury.
The injury flared up the day after the Chiefs' win against the Force last weekend.
It is Retallick's second shoulder injury this season, having missed five weeks earlier in the competition after hurting his other shoulder.
The All Blacks lock will therefore miss the Chiefs' match against the Rebels on Saturday and the top-of-the-log clash against the Hurricanes in Wellington on 16 May.
Chiefs coach Dave Rennie has made a number of changes to the side that beat the Force in Hamilton last weekend.
Pauliasi Manu and Ben Tameifuna come into the front row with lock Michael Fitzgerald taking Retallick's place in the second row.
Captain Liam Messam also makes a return, while Andrew Horrell gets a chance in the No 10 jersey, replacing Marty McKenzie.
Elsewhere in the backline, James Lowe returns on the left wing, with Tim Nanai-Williams shifting to the right wing.
Chiefs – 15 Tom Marshall, 14 Tim Nanai-Williams, 13 Charlie Ngatai, 12 Sonny Bill Williams, 11 James Lowe, 10 Andrew Horrell, 9 Brad Weber, 8 Michael Leitch, 7 Sam Cane, 6 Liam Messam (c), 5 Michael Fitzgerald, 4 Matt Symons, 3 Ben Tameifuna, 2 Hika Elliot 1 Pauliasi Manu.
Subs: 16 Quentin MacDonald, 17 Siate Tokolahi, 18 Jamie Mackintosh, 19 Michael Allardice, 20 Johan Bardoul, 21 Augustine Pulu, 22 Damian McKenzie, 23 Bryce Heem.
Photo: Hagen Hopkins/Getty Images