Justin Blackmon (WR, Oklahoma State) is a top-tier athlete. Despite being only 6'1", 207 pounds, Blackmon has great upper end speed, and he has a great vertical that makes him a threat at any time.
Basically, Blackmon is an all-around great prospect. He runs great routes, can adjust to poor passes, and he keeps defenders off balance with his speed variation and crisp cuts. The Jaguars have been missing a top-tier receiver for a long time, and Blackmon could fit the bill for filling that void.
Still, most mock drafts have Blackmon disappearing from the board when the Rams pick at 6th overall. That poses a significant problem for the Jaguars, especially since wide receiver is their biggest position of need.
The Jaguars will likely have two options if they wish to address their receiving corp in the first round. They could trade up a few of picks, possibly to the Browns' position at number 4 overall, or they could trade down to around the 15th pick of the draft and hope to draft Michael Floyd. the discussion on Floyd is for another day however.
Final thought: Justin Blackmon makes all the sense in the world for the Jaguars. If by some miracle he slides to 7th overall, I'd be livid if they didn't snatch him off the board, but the Jaguars can't bank on that if they're the guy they identify as "their man." The Jaguars have indicated that they'd be willing to entertain the idea of trading down, but I wonder if they're willing to trade up.