ANAHEIM — Jacob Trouba is a Living Lesson for Chris Drury, and the lesson the Rangers general manager must learn from all of this season’s unpleasantness is that when business needs to be taken care of over the offseason, business needs to be taken care of over the offseason, regardless of how tricky and distasteful that might become.

Drury’s Greatest Mistake was on full display on the ice Friday, wearing No. 65 in some garish costume for the Ducks, a few hundred feet below the press box from where the GM watched his team collapse after holding a 4-2 third-period lead before falling 5-4 in overtime on late goals for their ninth defeat in 12 games (3-7-2) that kept the Blueshirts from vaulting into a playoff spot.

The mistake was not what you might have been told before.

The mistake was made when Drury did not play country hardball over the summer and instead deferred it to the edge of winter, when by that time, massive structural damage had been incurred on and off the ice.