Lets see:
Lions lost Tj Lang for 10 games last year (he was injured in at least 4 more)
Lost Golden Tate for 9 games (traded)
Lost Marvin Jones for 8 games
Lost Kerryon Johnson for 6 1/2 games ( he didn't play much in the first 2-3)
Lost Eric Ebron (let go) and picked up a useless Luke Wilson
Plus a myriad of other injuries to the O-line (he had 40 sacks)
So yeah, Stafford Stats sucked last year, happens when you lose your number 1 and number 2 WR, your best receiving TE, and your starting RB. Go figure. Stafford receiving corps resembled the 2017 Bears, minus a Jordan Howard.
Face it, Right now, Mitch couldn't hold Cousin's or Stafford's jock strap, let alone Rodgers. Had the Bears had any of the three, they would have been SB contenders last year.