So why didn't the Sabres send down Dahlin then? Why has any team kept their players from the 2018 draft in the NHL?
Fact is, Dahlin is doing more in the NHL this season despite being a year younger (in terms of hockey experience) and being European, having to translate from the big rinks and a much different game than what is being played in North America. That is not easy as history has shown, and it takes time.
On top of that he's an 18 year old defenseman in the NHL (which in itself is extremely rare) playing around 18 minutes a night, being +4 on a team who has been really bad the last couple of years and he is on pace for around 32 points.
I'd expect his offensive game to improve as the season goes on. His focus is most likely on getting the defensive part of the game down in the NHL first. The offense is there, no question about it, working on the defense is much more important at this point and so far he's doing a real solid job on it as any Sabres fan will tell you.
Even Drew Doughty (who, like Bouchard came from the CHL, was a late birthday and a year older than Dahlin) 'only' put up 27 points and was -17 in his rookie year. Didn't stop him from turning out to be an alright defenseman.
The difference between Dahlin staying with the club and Bouchard being sent down is not based on skill but rather the number of protection spots.
The latest expansion offered two options: 7 Forwards, 3 Defence, 1 Goalie or 8 Players, 1 Goalie.
This puts the Oilers in a tough position for players to cover.
Just looking at defence for each team the retention for the D-core looks something like this:
Oilers: Nurse, Klefbom, Larsson (with Bouchard not being eligible for selection)
Losing: Forward outside of top 6 or Benning, Jones, etc.
Sabres: Ristolainen, Dahlin, Beaulieu (Scandella & Bogosian will be UFAs after year 2)
Losing: Most likely a middle 6 forward.
Sabres will be able to cover Dahlin while not losing a major piece. Oilers, if Bouchard stayed up, would be looking at losing one of Klefbom, Larsson, Nurse, or a forward outside of McD, Nuge, Drai, Looch (NMC).