I was just looking at some stats the Rebels have used 37 players this season with 14 players who played their first game for the Rebels and 12 of those who made Super Rugby debut (although that includes experienced players like Mafi and Day).
Here is a list of players and number of matches they have lost through injury this season (+1 relates to players who miss tomorrow's game as well):
Sean McMahon 9
Toby Smith 7
Lopeti Timani 6
Jordy Reid 5
Dom Day 4+1 = 5
Sefanaia Naivalu 3+1 = 4
Nic Stirzaker 3+1 = 4
Colby Fainga'a 3
Jack Debreczeni 2+1 = 3
Mick Snowden 2+1 = 3
Mitch Inman 2
Marika Koroibete 2
James Hanson 1
Plus then you have the players who have been injured all season 10+1 Pama Fou, Sam Jeffries, Rob Leota, Tim Metcher, Dom Shipperley, Alex Toolis.
Not sure if Ah Nau and Fox have been injured.