They could always flip Rielly, it's not like he's got a bad contract by any means. They've already got Liljegren, Sandin, Giordano, Brodie, Holl, Timmins, Muzzin (he'll either be back or on Robidas island), Niemala, along with depth in Benn and Mete.
Their defensive play without Rielly as a team was elite, like top 3 league-wide. Rielly doesn't help them keeping the puck out of the net.
They can keep Meier along with Nylander, Marner, Matthews, Tavares if they really wanted to. It's not hard. The Leafs don't have bad contracts as a result of paying their top guys premium. Tavares might be considered their worst contract but even he's ppg in year 5 of his contract.