It's like many of us said ... the TE position takes a LOT of learning to transition from college to the NFL. In the limited training time of college they tend to either be big WR's or lean OT's, but rarely both, almost never featured, and have very limited assignments. In the pros, coaches have to use the TE to do a LOT more things as those creative defensive coordinators exploit the edges constantly. So way more routes to learn, exponentially more pass protection assignments, waaaaaaaaaaaaaaaay more run blocking assignments, and hot reads out the wazoo. The guys that make it to the NFL typically are guys who got by being bigger and faster than the collegians they were matched up against, so they didn't need to be assignment-sound ... they just showed up and dominated. It's a culture-shock position, because the NFL they're just another rookie with more learning than their entire football experience to that point.
Yeah, rarely does a TE become instantly successful in the NFL, and when they do, it's usually the result of an offensive coordinator who game-planned for them to do the same things they did in college, such as Jimmy Graham being a big WR, or Aaron Hernandez being a big slot WR. Even Gronk was mediocre as a rookie, and he had a full year off rehabbing his back to study the stuff. TE is one of the biggest challenges to transition from college to the pros. Gesicki isn't there yet, he's a work in progress.
But, I'm very happy to see him blossoming. He has the ability, work ethic, and attitude to succeed tremendously for us. I'm looking forward to watching it happen.