If it's true that Manning is a little flat or a bad fit for this offence why not work out Kapernick?
He's certainly the best talent out there and would obviously demand snaps and a couple series a game which could translate into some explosive plays which consequently could also mean Wins.
Just to add I don't know why they would be down on Mannion unless they are looking for a more mobile backup.
I wonder if Baltimore. Could be interested in him and the Rams Could be setting up a trade at the same time as a Kapernick signing. I'd be ok with that.