This is great.

One thing I am noticing is that the WRs who are considered elite tend to have great rookie seasons and very few 1st round WRs who don't have even a little success year 1 ever become impact players. Demarius Thomas looks to be the best of the WRs with fewer than 300 yards receiving. Mike Williams is the only 1K yard receiver in that list with fewer than 100 yards that I see.

Seems like you either have it from the start or you never have it, with very few exceptions.

@aussie61, you said Dantzler...I assume you meant Gladney?

Glad you enjoyed it.
Certainly it seems that the rookie year does give a good indication on a players trajectory.

Well that's what should happen,but with little practice time together,will Kirk trust JJ or go to where the chemistry is with Adam and Rudy. 

Not sure what you mean by physically gifted... speed, strength, agility, height? It looks like many tall receivers have great first years. Evans, Benjamin, Green, Jones... Moss' height was certainly an asset, and we know it was one of many! Because route running improves with NFL experience, it may be that physical gifts play a bigger role than route running in rookie WR success.

It is also true that poor route running can make a WR a bust: Treadwell.

Average and even shorter shorter receivers have success as rookies too: Harvin, Diggs, OBJ. We know Diggs' route running and understanding of the game is a reason why he became a starter as a rookie. So while Jefferson is not 6'4", at 6'1" he is taller than most cornerbacks, and he was the best at contested catches in college. He has many outstanding physical traits, and his route running is also a strength. He also has the opportunity to be WR2 with a highly rated QB. Assuming a 16 game season, Less than 50 catches means he is not a strong WR2 or not the WR2. 64 or more and he could have 900 plus yards. I expect 60+ receptions and above average YPC.

Arif at The Athletic has a nice writeup on the Receivers. Here are JJs strengths:
Many of his strengths match that of the departing Diggs and newfound receiving partner Thielen, potentially making his transition into the offense relatively easy. Jefferson worked in an NFL-style offense under offensive coordinator Joe Brady at LSU and many of the concepts he’ll be asked to work with in the NFL will mirror what he learned in college. He has great body control and ball tracking and, per PFF, had the best contested-catch win rate of draft-eligible NFL receivers. His catch technique is close to ideal — does a great job looking the ball in, catching the ball outside of his body and frames the catch with his hands. Does a good job as a route-runner generating space, primarily through quickness and deception. He varies speed in-route to bait defensive backs and boasts remarkable suddenness as a route runner. Great hesitation and double-moves, with foot fakes and head fakes in his repertoire. Has impressive strength for his size, shows up both at the catch point and in his ability to generate yards-after-the-catch as he breaks tackles. Scored extremely well on Vikings’ psychological testing. theathletic.com/1921399/2020/07/11/vikings-training-camp-guide-wrs-all-eyes-on-adam-thielen-heading-into-season/ To read it you need a subscription.

I heard a lot about Adams as his comp in the predraft process

Good stuff

I don't think anyone should expect Jefferson to fill up the stat sheet with Diggs numbers as a rookie. We'll have to hope AT stays healthy and we get significant contributions from Sharpe and Irv Smith to help fill the void.