BTW not signing rocker still is very costly for the Mets.
First of all the Mets probably did save at least a million with their other picks to sign rocker. 1 million is about equivalent to a late second rounder and could have been used to sign better 2-9 picks (maybe an extra HS prospect instead of a college senior). Since those guys where already signed when rocker fell through the Mets never get that draft capital back. Of course cohen keeps that money in his private pocket but draft capital is way more valuable that real dollars to teams (estimations are 4-5 times https://blogs.fangraphs.com/an...o-value-draft-picks/)
Apart from wasting that draft capital saved for over slotting rocker they also went from 10th to 11th pick. From a pick alue standpoint that is no big deal but it means their pick is now not protected and they can't sign a guy with a comp pick attached to them without losing that pick. Usually a comp pick is more a late first rounder which hurts too but is not nearly as bad as losing the 11th overall.
That limits their options in the off season albeit they got scherzer who had no pick attached (for big money).
They probably had to pay scherzer the no comp attachment (which rises his value), so overall that decision still probably cost the Mets like 15 million of value (the million not spent in the draft is valued at around 5 million and the no comp attachment probably cost another 7 or 8)