The 2015 NFL Supplemental Draft will be held on Thursday, and there's a chance that Clemson offensive tackle Isaiah Battle will get picked. It's unlikely that any of the other six players who are eligible for this year's Supplemental Draft will be selected, but I suppose that possibility can't be completely ruled out.
Even if only Battle is picked in the Supplemental Draft, the other six players will then become undrafted free agents, and there's a good chance some of them will sign with teams before training camp begins. That's why teams are scouting these other players even if they have no intention of submitting a pick for them. Case in point:
Before the actual 2015 NFL Draft, the Detroit Lions brought in several wide receivers who can also return the ball, but they didn't actually pick any of them. Now, with a roster spot open, perhaps the Lions will decide to bring in North Carolina Central's Adrian Wilkins to compete for the return job. Any rookie who joins the team this late in the offseason is probably going to have a tough time making the 53-man roster, but a player like Wilkins could certainly be worth a look during training camp.