Don't expect a massive massive return for Marner, not a lot of teams want to invest in a 11M winger that is playoff liability and for the fact he's 11M.
Subjective on the word massive obviously. That said, he was handled well by a team that plays heavier, defense and of course has strong goaltending. Both Matthews and Marner were large in part taken out of being a factor. That said, Marner can add a dynamic factor to a heavier team that needs more play making ability. Paired with a good North South defensive forward that can punish people and create space for Marner and a a sniper, he would probably do better against heavier teams.
marner's cap hit could be a roadblock, but teams that are just looking to make the playoffs aren't going to care too much about how he performs in the playoffs, they just want him to get them there.
that been said i don't see him getting traded unless a team makes an offer dubas can't refuse, i don't see dubas shopping him around just for the sake of unloading him.
Marner won't be moved i think. It is still too early in his career to give up. Unless the deal is great I say he stays. Now if he has another lackluster playoff performance next year he might want to leave Toronto just to get away from angry fans.