Ok. What changed

My feeling is that he wasn't injured, but this is the kind of drop-off when an over-40 athlete underestimates how much more rest/recovery he needs, compared to even a few years ago.
If younger players have trouble playing the Thursday after a Sunday game and are ground down without a bye week during the season... maybe Sunday-to-Sunday for more than a few games will be too much for a 41 year old. (And healthy college-age players usually "hit the wall" their rookie year.)

My feeling is that playing AR every other game (or 2 out of 3), forcing him to treat the off weeks like a bye (complete rest and recovery), would get you peak AR (like he was younger) for the games he does play. That would be a huge risk (if he gets rusty, or injured anyways), but expecting him to just "play through it" every week will just accumulate more fatigue.

 

And what you said was wrong. It wasn't even Gainwell's first big game this season. He ran for 99 yards and two touchdowns and caught six passes for 35 more yards in the victory over the Vikings.

 

Yet he put up those great numbers in a half.