If a guy had 112 points last year, how many will he have this year?

I'm looking at you, Henrik Sedin. If we look at 115 players who put up roughly similar point totals over the last 40 years, we can see that it's not likely to be 112 again:

Remember - players who do amazing things in one season typically do them because everything broke right for them: only 1-in-5 of our similar group maintained or exceeded his scoring totals the following season. Of course, that group of players has a very different profile from a playmaker like Henrik Sedin. What if we look at other playmakers? Well, we only end up with 18 player-seasons, from a dozen players:

That drop-off doesn't look so harsh - but these players took 50% more shots than Henrik Sedin and were actually underperforming in the shooting department, unlike Henrik, who was vastly overperforming his career 13.1 shooting percentage. If we go back through NHL history, there are very few players who had a season like he just did: Craig Janney and Adam Oates are obvious comps, and Doug Gilmour and a late-model Wayne Gretzky also accomplished similar feats. So when we've got no one to compare him to, what do we do? 3-2-1 projections...

All this is is an average of Sedin's last three seasons, weighted 3-2-1. And since he's turning 30, the projection should probably be slightly more pessimistic. If you're picking Henrik Sedin in a hockey pool, reasonable expectations put him a shade above 90 points. It's possible that he learned to shoot and became a more efficient playmaker at age 29...But it's highly unlikely.