Front rower Afoa suffered a suffered a dislocated elbow and Harris a knee injury in the team's loss to Cronulla last round.
Afoa is expected to be sidelined for six weeks while the recovery for second-rower Harris is four-to-six weeks, depending on how he comes through surgery.
There are several changes for the side this round with Simon Mannering moving from loose forward to the second row to replace Harris while Adam Blair makes a timely return from a one-match suspension to reclaim the No 13 jersey.
Afoa's out of the side for the first time this season and his spot on the bench going to Ligi Sao who comes up from the reserve team and will play just his fifth NRL match.
There are three changes in the starting backline with first-choice wingers David Fusitu'a and new Kiwis international Ken Maumalo both back while Peta Hiku moves from the right wing into the centres.
Gerard Beale, who was on the left wing against Cronulla, is on the bench.
Issac Luke, Hiku and James Gavet are all nearing personal milestones.
Luke will move within four games of his 250th career appearance, Hiku within four of his 100th and Gavet will be just two short of his 50th.
Captain Roger Tuivasa-Sheck is seven games away from his 50th outing for the Warriors and Mannering nine from his 300th.
The Warriors sit fifth on the NRL ladder on 22 points with a 10-5 record.
The Panthers are on the same points but sit fourth on points differential and a win would take the Warriors back into the top four.