So, just to be clear, this isn't every player in the league that you think is a HOF after this season ends. Specifically this is players you didn't think were at the end of last season or were fence sitting on but now you do. (So leave the Crosby, McDavid, Malkin, Kanes etc out who were obviously HOF'ers prior to this season).
A few to consider:
Auston Matthews: I had him as a HOF already prior to this season but not everyone did. Surely becoming only the 10th player in NHL history to have two or more 60 goal seasons + 3rd Rocket Richard trophy in 4 seasons makes him a lock even if he retired at seasons end.
Roman Josi: I was a fence sitter for him prior to this season but a season where he will finish likely around 85 points and garner a top 5 Norris finish, he's in.
Cale Makar: It was a controversial opinion to say he would have been in end of last season with so few games played but nonetheless many said he would be. Now that he's added another season to his resume with likely 90+ points and almost for certain another Norris finalist (I think Hughes wins but Makar could). He will have 4 Norris finalists, 1 Norris, 1 Smythe, 1 cup, Calder, over PPG through 310+ games.
Brad Marchand: Has an additional season of compiling gotten him there?
Artemi Panarin: Likely finishes around 115-120 points, and finishes with almost exactly the same number of career points as Pavel Bure who is already in the HOF. This is his 4th time getting 90+ points and 6th time getting 80+.
i would've had matthews in already. the other four are very interesting and i probably agree - makar being the weakest of the bunch only due to the least longevity, but you're right that 4x top-3 norris with a cup and smythe gets him in. for him, adding a season at basically his career average level is the big difference maker.
panarin and josi are perfect examples of guys who possibly tip on the other side of the fence if they had just totally fallen off this year.
marchand i'm less convinced - he was probably already in, and i don't think this year has done anything particular to help make his case, aside from maybe now being the captain of an O6 franchise and hitting some milestones (he'll break 400 goals).
also think pastrnak fits this bill, with a similar case to makar, but with more seasons under his belt. hardware wise he was probably close already; whether or not he gets in on if he doesn't play another game depends on why that's the case (tragedy/injury vs he decides he's bored of hockey)
pavelski is an interesting option that was mentioned. as stupid as it sounds, i think he's one season away still. i don't think this season, as impressive as it is at age 39, pushes his totals high enough - but if he hits 500 goals and 1100 points at age 40, i think it would.
kucherov, pietrangelo, and hedman are already in, for me.
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i think next season we can start to think of guys like marner and tkachuk as being "on the fence", where a big season gets them on the right side of things, even if they don't compile much further. but i don't think anyone considers them there yet. if hughes wins the norris this year, add him to that list too.