According to Pro Football Talk, Roger Goodell, with the backing of the NFLPA, will suspend the former Ohio State quarterback upon his entry to the league for “decisions that undermine the integrity of the eligibility rules for the NFL Draft.” The memo from the NFL states that "Pryor had accepted at the end of the 2010 college football season a suspension for the first five games of the 2011 season for violating NCAA rules. Pryor will be ineligible to practice prior to or play in the first five games of the NFL regular season after he signs."
The supplemental draft originated in 1977, and was created to cater to players who either missed the filing deadline for the regular draft or instances such as Pryor's, where the player faced disciplinary or eligibility issues in college.
Pryor's Ohio State suspension was handed down in December, when the NCAA ruled that Pryor and four of his teammates at Ohio State had, among other things, traded signed memorabilia for tattoos, a blatant rules violation.
The idea of carrying over improprieties in college over to the professional level is a somewhat strange precedent to set by the NFL, particularly in the wake of the recent Yahoo! Sports report that implicates several current NFL players who attended the University of Miami and allegedly violated numerous NCAA rules while there.
In April, NFL draft guru Mel Kiper projected Pryor to play tight end at the professional level.
UPDATE: Alex Marvez of Fox Sports reports that the NFL's ruling on Terrelle Pryor is not based on the NCAA suspension.