I would imagine the price would be similar to what Martinez got from Vegas. Due to uncertainty on staying healthy, a little less term, as well as cap constraints for Toronto I'll change up the trade a bit.
How about this.
To TOR
Nik Hjalmarsson (25% retained = 3.75M)
To ARI
Andreas Johnsson
2021 4th*
*if Hjalmarsson plays 35 games the 4th is upgraded to a 3rd, if he plays 55 games it is upgraded to a 2nd
Since Johnsson's contract was front loaded as well as this years signing bonus already being paid he is a good money saving middle 6 player for Arizona. Also Hjalmarsson is only owed 2M more for this upcoming season a 25% retention only costs the Yotes 500k.
For Toronto they move out an excess middle 6 winger and bring in a legitimate top pairing shut down guy (arguably the best shut down D in the league when healthy), while only taking on an extra 350k cap.
*Edit: just noticed the leafs dont have the available picks for my conditions due to the Clifford condition. Maybe make it 2022 picks instead.