Fantasy Football nerds, listen up ... Jake Plummer says he's expecting a monster year from Justin Herbert -- telling TMZ Sports he thinks Jim Harbaugh will get the very best out of the Chargers star.
Plummer played in the NFL at the same time as Harbaugh in the late 1990s -- and it's clear as day he grew a ton of respect for the Bolts' head man. So much so, he believes Herbert's game will soar to new heights under his tutelage.
The former Arizona State star quarterback says because Harbaugh wasn't the most athletic signal-caller, he grew a massive football IQ .