A cursory search brought up these results regarding why Graham was brought on board.
Here, Carroll talks specifically about Graham's ability to catch passes in crowds and put up points.
http://www.seattletimes.com/sports/...roll-on-jimmy-graham-marshawn-lynch-and-more/
"It’s pretty clear, he’s a big receiver, plays big, makes plays in a crowd, makes plays on top of guys, he’s a very effective player in the red zone, he has been a terrific, consistent scorer..."
Here, at 1:21, Schneider speaks specifically to Graham's red zone production.
http://www.seahawks.com/video/2015/03/10/john-schneider-deal-graham-was-one-we-had-make
Then here, in September, Bevell basically admits to using Graham as a decoy for the other receivers.
http://www.seattletimes.com/sports/...n-jimmy-graham-hell-continue-to-grow-with-us/
"We talk so much about Jimmy since we’ve got him, but look at what Doug Baldwin did at the end of last year, Jermaine Kearse has always been a staple, Tyler Lockett you can see how he’s coming on and becoming a big part of us... There’s playmakers all over, and
Jimmy can dictate coverage and help out those other guys, those other guys start playing then they dictate coverage and help Jimmy.”
In that same article, Bevell defends Wilson for ignoring a single-covered Graham in the endzone for Kearse instead.
It's not a stretch to wonder if Bevell has zero say in acquiring Graham, and possibly even resents being told who to use. Evidence suggests that Bevell is a very stubborn OC, hesitant to adjust for other defenses, or even his own offensive lineup.
How anyone could defend Kearse over a TE on track for the HoF is beyond me, but the larger question is: will Graham ever be welcome in this offense?
This is conjecture, but I believe Bevell has stuck around for so long because of his rapport with Wilson (Bevell, too, is a former Wisconsin QB). And I wonder if he's telling Wilson not to buy into Jimmy's hype and to instead trust his (Bevell's) gameplan, whereas a different, more disinterested OC would say flat out, "Russ, that's Jimmy effing Graham out there, just throw it up for him." You don't call plays in the red zone, you call players. Insisting on Kearse over Graham in the end zone will never cease to amaze me, and it's a microcosm of why Bevell needs to get out of town, and out of this offense's way.
*For the record, I don't think Graham needs
more targets, per se, I think he needs
smarter targets.