He's definitely on pace for the 2nd best rookie season this era as he's on pace for (or already ahead of) all the rookie seasons by the best recent tight ends except for Shockey. I also looked at some of the rookie seasons of some of the great historical TE's, and only 3 had better rookie seasons. Here are the rookie seasons i've compiled:
Keller - 53 receptions, 613 yards, 3 tds (Projected)
Rookie season's Keller is on pace to beat (or already beat):
Gates - 24 receptions, 389 yards, 2 tds
Tony G - 33 receptions, 368 yards, 2 tds
Witten - 35 receptions, 347 yards, 1 tds
Winslow - 5 receptions, 50 yards, 0 tds (injured)
Dallas Clark - 29 receptions, 340 yards, 1 tds
Heath Miller - 39 receptions, 459 yards, 6 tds
L.J. Smith - 27 receptions, 321 yards, 1 tds
Todd Heap - 16 receptions, 206 yards, 1 tds
Cooley - 37 receptions, 314 yards, 6 tds
Crumpler - 25 receptions, 330 yards, 3 tds
Eric Johnson - 40 receptions, 362 yards, 3 tds
Randy McMichael - 39 receptions, 485 yards, 4 tds
Zach Miller - 44 receptions, 444 yards, 3 tds
Older TE's he's on pace to have better seasons than:
Ozzie Newsome
Shannon Sharpe
Dave Casper
Jackie Smith
Mark Bavaro
TE's that had better rookie season's than Keller is projected to:
Shockey - 74 receptions, 894 yards, 2 tds
Keith Jackson - 81 receptions, 869 yards, 6 tds
Mike Ditka - 50 receptions, 1076 yards, 12 tds
John Mackey - 35 receptions, 726 yards, 7 tds
Keller - 53 receptions, 613 yards, 3 tds (Projected)
Rookie season's Keller is on pace to beat (or already beat):
Gates - 24 receptions, 389 yards, 2 tds
Tony G - 33 receptions, 368 yards, 2 tds
Witten - 35 receptions, 347 yards, 1 tds
Winslow - 5 receptions, 50 yards, 0 tds (injured)
Dallas Clark - 29 receptions, 340 yards, 1 tds
Heath Miller - 39 receptions, 459 yards, 6 tds
L.J. Smith - 27 receptions, 321 yards, 1 tds
Todd Heap - 16 receptions, 206 yards, 1 tds
Cooley - 37 receptions, 314 yards, 6 tds
Crumpler - 25 receptions, 330 yards, 3 tds
Eric Johnson - 40 receptions, 362 yards, 3 tds
Randy McMichael - 39 receptions, 485 yards, 4 tds
Zach Miller - 44 receptions, 444 yards, 3 tds
Older TE's he's on pace to have better seasons than:
Ozzie Newsome
Shannon Sharpe
Dave Casper
Jackie Smith
Mark Bavaro
TE's that had better rookie season's than Keller is projected to:
Shockey - 74 receptions, 894 yards, 2 tds
Keith Jackson - 81 receptions, 869 yards, 6 tds
Mike Ditka - 50 receptions, 1076 yards, 12 tds
John Mackey - 35 receptions, 726 yards, 7 tds