I don't understand the hypothesis that Monahan shouldn't be on a contender's second line. "if Monahan is your second-line centreman then you're not a contender.
I won't even use Vancouver as an example because Vancouver actually had pettersson and JT miller on separate lines for the majority of the season, so we can suddenly go back to that system.
I will use Boston Winnipeg and Colorado. These 3 teams are one of the best teams in the NHL. currently one of the few contenders in the league. So if they added Monahan to their team they are suddenly not contenders?
right now Monahan has more points than Colorado's next highest centermans. 27 year old Ross Colton on paper in Colorado's second-line centerman, has 23 points.
Winnipeg's second line centerman has as many points as Monahan.
Sean Monahan also has more points than Boston's second-line Winnipeg and Colorado's current second-line centerman, but those teams are contenders.
Sean Monahan would be an excellent addition (without moving any current roster pieces) to any of these teams at the moment and it wouldn't change their positions of not suddenly being contenders. For Vancouver, if we do Lotto line our way, then we can have a legit proven second-line centerman in Monahan center it. If not, we can move Monahan as a winger too. Lots of options. MY point is, Monahan will be an ok second-line centerman for many of the top 10 teams, and I used 3 examples. Well, 4 including Vancouver.
Edit
I'm gonna look at 3 more teams. Last year's Cup finalists.
Vegas knights. their second line centerman has 26 points. Monahan also has more points than him.
Florida panthers, damn, , their top 3 centermans have over 45 points.
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Rangers top 2 centermans ok, they are very productive.
Flayers second-line centerman holy cow he only has 20 points.
He will be a welcomed addition for many many playoff-bound teams.