In Toronto, Petr Mrazek is signed through this season and the next two at $3.8 million. If the Leafs intend to retain Jack Campbell's services, that money likely needs to move. Mrazek has not had a good start to his time in Toronto, and would probably agree to move to a new situation after being thoroughly outshined by Jack Campbell, who is receiving the lion's share of the work. In Edmonton, Mrazek would have a chance to take over the number 1 goalie slot.
Mikko Koskinen is drowning in Edmonton. The media is torturing him, his defence is non existent, he's been thrown under the bus by his coach, and he just does not seem happy. He desperately needs a change of scenery and I doubt the Oilers management group would have much of a problem letting him go somewhere else.
Neither goalie has had a fun time this year. Mrazek has struggled in the few games he's managed to be healthy enough to suit up for, and Koskinen has been thrown to the wolves completely. Both goalies could use a fresh start.
Mrazek could provide the Oilers with an upgrade to their tandem with Mike Smith for next season and give them some stability for the 23-24 season as well. His cap hit is lower than Koskinen's as well.
Koskinen could be a serviceable backup for the Leafs until the end of this season and is capable of taking on a larger workload than Mrazek appears to be, but the real benefit for the Leafs is that his contract expires at the end of the season, freeing up cash for Jack Campbell's new deal.
This deal could work on multiple levels for the Leafs. Mrazek arguably has more value than Koskinen. To even out the trade, the Leafs could demand that Edmonton retain a portion of Koskinen's remaining contract bringing his cap hit down to the $2.25M-$3.8M range. This gives the Leafs possibly an extra $1.55M in space to add in other areas at the deadline, or at the very least, washes with Mrazek's current $3.8M cap hit.
While on the surface it seems crazy, this really could be a deal that benefits both teams. I believe with some retention on Koskinen's contract, the value for each team are about even. The biggest thing for the Leafs is cap space. For the Oilers, they desperately need a change in goal, and Petr Mrazek could be a much needed upgrade between the pipes for them.