Knight makes the move from the Raiders with 10 first-grade appearances to his name, while Denniss has featured 18 times for the Newcastle Knights.
Rabbitohs General Manager of Football, Shane Richardson, spoke to the club’s website about the two inclusions, and believes both players will help add depth at Redfern.
“Liam is an old-school front rower,” Richardson told rabbitohs.com.au.
“He is not one to take a backward step and will push strongly for a spot in our forward pack for the start of the season.
“Cory is a big-bodied back who has a similar build to Campbell Graham, another young gun in our backline.
“He has had a taste of first grade and knows what it will take to crack into our best seventeen.
“We look forward to Liam and Cory creating competition for spots by working hard and putting in his best efforts at every opportunity, as is The Rabbitoh Way.”