At this time the Leafs will be similar to the Pens, in that their elite core forward group will then be surrounded by young players who are on Entry Level Contracts or on contracts not worth that much, like the Leafs are doing this season with Tyler Ennis at 1y/650K. The Leafs have several promising young wingers who could compete for roster spots as early as training camp in the Fall, although the Ennis signing has likely put that chance to rest. By the time Patty is gone players like Kappy (Who are currently limited to bottom 6 roles due to the depth of the current team) will be able to fight for roles that fit their true potential of a top 6 forward. The 4C role for long-term is poised to be filled by former Regina Pats captain Adam Brooks, and he will be joined by current Marlies such as Mason Marchment, Pierre Engvall, and Carl Grunström (Who if not for the Ennis signing would most likely have been the 4th line Left Winger this season).
In my opinion, most of the future D core is already within the organization, as Reilly and Dermott are already on the team, Lily will for sure be on the team come Fall 2019 if he does not already make an appearance in the NHL this season, and the Leafs also have several talented prospects such as Sandin, Rasanen, and Durzi who could fill out the 3rd pairing. From there, now comes the task that the current Leafs face, in finding solid D-men who are not too too offensive minded and who play solid DEFENSIVELY that will play with Reilly and Dermott on the 1st and 2nd pairings. In terms of the D-men on the right side of the top 2 pairings I have, it is not very likely but they are things that would be very nice to see come to fruition. Gardiner is not a part of the future, as, despite his offensive talent, his defensive blemishes are horrendous (No it was not entirely his fault for game 7 that fans should have created a GoFundMe page to buy out his contract), and his contract is up next year and will be asking for a raise that the Leafs cannot afford.
After this season, Sparky replaces Mac as the backup to Freddy.
The future is bright, continue to trust in the Shanaplan and the Stanley Cup will come home.
Really like the Josh Manson trade. Getting a solid defensive defensemen. I personally don't think Ryan Ellis won't sign with us, but it would be a unreal deal to lock him up.