Agreed, but without Marner knowing it, Treliving could be doing his due diligence homework behind the scenes currently .... Right now he is blocked by a NMC.
Teams interested in Marner's service have two obstacles, and that is completing a successful trade with Leafs GM that he would take, and also be prepared to meet Marner's future salary demands.
When the timing is right and BT has a trade he would accept he can then give that team permission to talk contract with Darren Farris directly even. BT however could also talk contract with Marner getting a good feel for his asking price on next contract to pass that info along to interested parties. Treliving would not re-sign him until he already had a firm commitment from another team on term, cost and price of assets exchanged in trade.
The real goal here is to complete a successful sign and trade deal (the sooner the better) where Marner is on board and then the current NMC becomes just a formality if all 3 sides can come to terms. My scenario was to show that from Marner's perspective IF the Leafs want to move on from him, it would be in Marner's best long-term interest to co-operate and participate because for him the end result is the same that his time in TO is over and he will be moving on and that is inevitable 1 way or the other.
PS. Don't forget about salary retention also where Leafs could agree to pick up a portion in order to facilitate a trade and even if it got to Marner with a new contract and no trade imminent (worst case scenario) without any trade protection a deal is still possible to see a successful trade without the contract being the issue. If the new team wants Marner at $10 mil AAV instead of $12 AAV then that becomes a part of the negotiation and factors into the exchange in the trade. Trading a re-signed Marner returns greater value then a 1 year rental and pending UFA would also to the other party as well when dealing away assets to obtain his services.
An 8th year (only possible for the Leafs to provide) otherwise it 7 years max could be a 8 year X $12.5 mil deal with a $2.5 mil Leafs retention, and a new team getting Mitch at 8 X $10 mil less than he makes now AAV. Just toss in pick(s) / prospects etc to compete a deal that Toronto would accept to offset retention costs/benefits.