Assuming our core roster is kept intact and none of our UFAs are signed, I don't see very many openings this season at forward.
Connor - Sheifele - Wheeler
Ehlers - Little - Laine
Perreault - Roslovic - Armia
Copp - Lowry - Tanev
Roslovic is a lock at this point. Dano and Petan will either be traded or used as extra forwards as they will require waivers next season and are both skilled players that can play up and down the roster. If they are traded then I can see one or two openings for fringe players like Lemieux or DeLeo, but I vastly prefer Petan or Dano. I don't think Lipon is skilled enough to be on the roster. Appleton has an outside chance of making the team, but it wouldn't surprise me if he did and I think Vesalainen will require a monstrous camp to make the team. I don't see the Jets rushing him to make the lineup but may give him a game or two before sending him down to the Moose. It's only a matter of time before Vesalainen is in the NHL, but I fear he wont be able to work on his offensive game much if he plays a bottom six role.
As for our defense, there will probably be openings as I don't think Enstrom will be resigned but wouldn't be disappointed if he was. I also highly suspect that Myers will be traded for cap space sometime before the season, especially if Stastny resigns. Kulikov is also a trade candidate, but I doubt anyone would touch that contract.
Morrissey - Trouba
Niku/Morrow/Chiarot - Byfuglien
Niku/Chiarot/Kulikov - Myers/Poolman
I think Niku is too skilled to not get at least a few games to start the season so I have him in my lineup. If Myers is traded, one our our LHD would need to make the transition to the right side or hope that Poolman can play consitent enough for a bottom pairing D-man. Morrow will be resigned but he can always be traded or placed on waivers if he doesn't make the team during training camp.
In short, I think these players are skilled enough to make the jump to the NHL next season in some capacity:
Roster players:
Roslovic
Niku
Petan
Vesalainen
Appleton
Poolman
Fringe Players:
Lemieux
DeLeo