The last two years he's scored an absurd number of goals for the number of shots he's taken.
Since Lee doesn't put up a lot of assists, his offensive production is largely tied to that shooting percentage, and he's not exactly a high-volume shooter...at least relative to most guys who are putting up 30+ goals. Consider that shooting 18.5% over 195 shots nets you 36 goals, while shooting 12% over 195 shots leaves you with only 23 goals. There's a pretty vast difference in value between a 36 goal/58 point forward and a 23 goal/45 point forward.
Before you say that 12% is unfairly low, it's still a good bit above what the average forward shoots (~10.8% since 2005). Lee's career shooting percentage before the last two years was 11.1% over 180 games. The reason why I picked 12% as a reference point is below the break, for those that are curious.
Anyway, at some point Lee's shooting percentage is almost certainly going to come down from its lofty heights the last two years. Heck, Stamkos just shot 12.7% this year at age 27, and he shot in the 16-20% range from age 19 through 25. Fluctuations happen, and shooting percentages tend to decline (on average) into your 30s, anyway. IMO, the teams interested in signing him to his next deal would be wise to temper their expectations.
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For those who want some context for those shooting percentage numbers, here it is:
The number of players who can sustain an 18.5% shooting percentage, or what Lee has averaged the last two years, is absurdly small. Only 29 players since the 1967 expansion have done it (minimum 70 goals and 160 games played), and 23 of them never played a game after 1995. None are currently playing.
There are six active players with at least 70 career goals (min 160 games played) who have a career shooting percentage above 15%: Byron (18.0%), Stamkos (16.7%), Marchand (15.8%), Henrique (15.5%), Stone (15.5%), and Hudler (15.0%). Lee ranks 11th on that list at 14.6% for his career.
If you sort younger, active players (age 33 or less) by career goals scored, there are 94 forwards meeting the criteria with 175+ career goals...a number Lee should almost certainly reach by that age. Stamkos and Marchand are the only two on the list with a career shooting percentage above 14.8% which means 98% of the group is below that number...with 96% being below 14.6%, and 89% being below 13.8%. The median value for this group of younger prolific goal scorers is 12.0%, which is why I used that number above. Approximately 78% of the group is above the average forward shooting percentage of 10.8%.
The moral of the story is that prolific goal scorers (even elite ones) have a very hard time sustaining 14.6%+ shooting percentages over the long haul in the modern NHL, with most coming in decidedly lower than that. Maybe Lee is one of the select few that bucks the trend, but I hope my team isn't banking on it.