i think it's a guy named craig johnson. i don't know much about him other than iirc, he was at tennessee last year. i don't know how much he works with him and how much bill musgrave (offensive coordinator) works with him - but i always see musgrave in his ear.
his game against san diego was a disappointment for me. he just isn't showing the consistency that i'm wanting to see.
imo, it's also now clearly evident that he can't make that deep-out throw or the sideline throw with enough zip (which will be at risk of being a pick-6). his passes also seem to float a lot and his slants don't lead the receiver well - it's either a bit high (putting the receiver in danger) or a tad bit behind, causing the receiver to lose YAC.
one positive is he's showing nice touch on the fly-passes - he puts a little air under the pass and allows the reciever to get to it - as shown by the 2 nice passes to harvin.