Chiefs have been vulnerable because they aren't putting up points like they used to.
They are relying on the offense to outscore the other team (which they cant anymore with only Kelce as the only dependable pass catcher) and then hoping the defense can bail them out when it's crunch time. Sound familiar?
He doesn't need to be productive in that offense though. He needs to be quick read and complete passes and then give the ball to CMC.
They don't ask him to win a game, they ask him to dump it off and keep the chains moving.