I would have thought the Reds have a couple of spare dollarydoos under the bed after Rodda, Hockings and Lucas bailed. At least Rodda would have been on big coin and I think Hockings would be making a decent wage, Lucas probably not in that league.
The Vunivalu deal was 'done' before those three jumped ship so I imagine that means they'd factored having the other three still on the books/money to re-sign them if needed. Of course no one really knows what the financial state of the game will be in 2021 with all the rumors of squad size cuts etc.