Evolution of the Cooks trade.

Once Watkins flew the coop for big $$$, the Rams were on the phone to every NFL team for a speedy WR (Hence, the OBJ rumors.)
When Watkins and Mike Williams scored the big $$$, Cooks' agent stepped away from the deal NE had on the table.
If unable to make a deal, NE would get no compensation for Cooks after this year, his 5th yr option.
Talks began between the Rams and NE and heated up at the owners meeting.
When McVay and Belichek met at a coaching clinic on Monday, they were able to hammer out a deal that just needed to be put to paper on Tuesday.

Kevin P.
Unlike Watkins, the Rams already work with Cooks' agent and are confident they can work out a deal before Cooks is eligible to fly the coop.