I wouldn't do this. SJax is your next flex guy after austin, and has no competition, a new contract to play for, and a team with a good defense and an injured #1 receiver. His attempts are about to go through the roof, and he has a real reason to fight for them entering a contract year. Yes, he's a little banged up, but he's playing through nicely I think.
Alf morris has a QB who poaches not only TDs but actual rushing attempts from him. This isn't a mcgahee/tebow situation where morris will still get rushes because griffin can throw the ball and the offense wants overall balance.
So my point being, from a sheer attempts standpoint, Jackson stands to see around 15-30% more. I don't think he's in that much worse a situation as far as talent/offense.
Wait on SJax another 2-3 weeks, this deal would probably still be there (unlucky injuries aside).
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AIM is like multiplayer notepad