Can't say I'm that interested in Roslovic if that's the key piece coming back... The Jets don't have a first rounder in this year's draft either.
I don't see a deal that make sense .. The only player that I really would want is Trouba. But a Kadri for Trouba deal doesn't work out value wise (nor for the Leafs cap).
Outside of the box idea: a deal of Kadri + Zaitsev for Trouba (with some additional +'s to balance it out since this favours the Jets IMO)... Assuming the Jets don't view Z as a negative asset, he plugs a RHD hole that is left by Trouba and Kadri shores up their centre position.
The Leafs could then re-sign Trouba long-term without significantly impacting the cap. A separate deal to land Colin Miller could then leave the Leafs with a d core of:
Rielly-Trouba
Muzzin-Miller
Dermott-Liljegren
Rosen/Holl
Nylander moves to a full time centre role up front. Opening a spot for Bracco, as I believe Brown will be moved as well. And since I've gone this far, maybe they move Marleau somehow.
Hyman-JT-Marner
AJ-Matthews-Bracco
Moore-Nylander-Kapanen
Mikheyev-Goat-Korshkov
... I love off-season dreaming