What does it take to be a top-five wide receiver in the NFL? Does Player X have to lead the league in receptions, yards or touchdowns? Must there be a noticeable dip in production from his position when he isn't on the field? How much does consistency weigh in?

Obviously, there's a lot to consider. As I thought more and more about what someone of that caliber must possess, I was drawn to three fundamental qualities: production, efficiency and reliability.

Production is the number one key to being a top-five wideout. Whether it be in terms of yards, yards after catch or touchdowns, a top-five wide receiver eats up yardage and puts points on the board almost routinely.

Efficiency and reliability almost go hand in hand. We can measure wide receiver efficiency by looking at how well they perform on a per target basis, which will be examined through our Pro Football Focus, Nelson dropped six passes on 91 catchable balls in 2013, and finished with the ninth-best drop rate at 6.59 percent among wideouts with at least 100 targets. Neither Johnson, Thomas, Marshall, Green or Bryant finished inside the top 20.

Lastly, the connection a receiver has with a quarterback is a great way to measure his reliability. One of PFF stats is wide receiver rating, which tells us what the quarterback's rating is when throwing at a receiver. Nelson finished 2013 with a rating of 111.6, the sixth-best in the league among receivers with at least 100 targets. The only receivers ahead of him were DeSean Jackson, Demaryius Thomas, Anquan Boldin, Keenan Allen and Eric Decker.

In essence, there's no doubt Nelson is among the best in the league in terms of efficiency and reliability. But when you factor in his all-around production, the consistency of that production and how it compares to that of his peers, Nelson falls just short of being tabbed a top-five wideout. We all know anything is possible with Aaron Rodgers quarterbacking your team, so he could just be one more massive statistical year away from making the leap into the top-five wide receiver conversation.