Horlin-Smith will miss the clash with groin soreness meaning Brad Hartman will play his first game since the Cats win over Greater Western Sydney in round 18.
Darcy Lang will come onto the Cats emergency list alongside Mitch Brown and Jed Bews.
The Cats made two changes at the selection table on Thursday night omitting Billie Smedts and Bews and bringing Jimmy Bartel and Jordan Murdoch into the side.
The Cats will have six players playing Saturday night who didn’t play in the round five clash between the two teams. Hartman, Allen Christensen, Josh Caddy, Steven Motlop, Jackson Thurlow and Shane Kersten will play the Hawks for the first time in 2014 replacing Horlin-Smith, Jackson Sheringham, Dawson Simpson, George Burbury, Steve Johnson and Taylor Hunt.
The Hawks meanwhile have five changes of their own from round five. Brad Sewell, Brian Lake, Jon Ceglar, Liam Shiels and Matt Spangher will replace Ben McEvoy, Taylor Durea, Cyril Rioli, Mitch Hallahan and Kyle Cheney from the earlier clash.
