Idk why people even bother to compare Ehlers and Nylander. It always ends up in fights and it's normally pointless because you're comparing two elite players with similar overall value. I'm going to do it anyway as I want to see their starts to the season. (Still makes me laugh someone added Drouin to this poll).
Nylander 5v5 (141 minutes):
Goals: 2
Primary Assists: 4
Secondary Assists: 0
ixG: 2.16
rel.xGF +/-: +0.15
rel.xGF: +0.01
rel.xGA: -0.14
oiSH%: 8.97%
Ehlers 5v5 (152 minutes):
Goals: 4
Primary Assists: 1
Secondary Assists: 4
ixG: 2.12
rel.xGF +/-: +0.58
rel.xGF: +0.35
rel.xGA: -0.23
oiSH%: 12.5%
So the difference in production is 9 points for Ehlers to 6 points for Nylander. The difference in minutes is negligible, but I do believe the production is not as simple as saying "Ehlers scores more at 5v5". Nylander has more primary points than Ehlers, but Ehlers' 4 secondary assists (T-2nd for forwards with Drouin lol) make his points look significantly better. Not to mention that ~3.5% more shots have gone in when Ehlers is on the ice compared to Will which potentially could mean "luck" is a strong reason for the difference.
They create xG individually at almost an identical rate, but Ehlers has been much better compared to his team in regards to driving xGF (they both have strong defensive results). The question becomes is Ehlers' *that* much better at driving offensive xG relative to teammates because he's *that* much better than Nylander? I doubt it. This is the first time since 2017-18 that Ehlers has had better rel.xGF +/- at 5v5 compared to Nylander. The real reason might be that the Leafs create 0.26 more xGF and 0.26 less xGA per game meaning Nylander's number look more "average" due to being on a "better" team (based on xG). The difference is large enough though to claim Ehlers has been much better at driving play both ways so far this season.
I think this season you can probably say that Ehlers has been the better player at 5v5, but taking everything into account I'd say it's not only close, but they've both been at minimum, borderline elite players.
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Nylander PP (24.8 minutes)
Goals: 2
Primary Assists: 1
Secondary Assists: 2
ixG: 1.67
Ehlers PP (20.3 minutes)
Goals: 1
Primary Assists: 0
Secondary Assists: 1
ixG: 0.27
This is where it's really not been close this season. Since Keefe decided that Nylander was someone that may actually be a good player (f*** you Babcock), he decided to not only put him 1PP last season, but when he split up the PP decided that Nylander should maybe get a good player or two to play with on the "2nd" unit. Ehlers has not only not been able to produce a lot yet, but his sexy ixG which makes him so good 5v5 has been almost non-existent on the PP so far.
To put Will's numbers into perspective, he's played 24.8 minutes so far. That ranks 116th minutes played by forwards on the PP so far. Nylander is T-23nd in points, and T-18th in ixG. Of the 36 forwards to have 5 or more points this season, only eight (including Will) of them have played 30 minutes or less (Huberdeau, Hintz, Tavares, Barkov, Hornqvist, Kubalik, and Burakovsky). Of the 19 guys that have Will's ixG or better, only three (including Will) guys have played less than 30 minutes (Tavares and Hornqvist). The dude has straight been elite on the PP in limited minutes because Keefe is trying to do an even split of the PP.
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Overall I'd probably give the edge to Nylander this season so far, but it might be a bit of bias. Ehlers has been better at 5v5, but it's not like Will has been a slouch there. The difference truly has been the fact that Nylander has been one of the best PP players in the entire league so far where as Ehlers has.... not shown much. Could that be because he's on the 2nd unit? Maybe. But we also gotta remember that Nylander plays on the 2nd unit too and doesn't have Mitch or Auston to help him out.