This phenomenon occurs for a combination of reasons, some of which include: the abundance of talent available relative to the length of the draft (now only seven rounds; it was 12 as recently as 1992), the inherent chaotic difficulty of projecting college players to the NFL, as well as players who flourish and develop later or with certain coaching in a specific system.
Some of the all-time NFL greats who fall into this category are:
Hall of Fame quarterback Johnny Unitas, a ninth-round selection (102nd pick overall, equivalent to a modern-day fourth-rounder) from the University of Louisville in 1955.
And the most recent ongoing example is future Hall of Fame passer for the New England Patriots and megastar, Tom Brady, who fell all the way to the sixth round in 2001 out of the University of Michigan.
Something else important to keep in mind when tracking the potential of players with this profile is that it rarely happens for them right away. The very nature of their draft slot often means there is something latent to their talent or missing in part from their overall play.
Late-round and undrafted prospects often have to outshine higher-selected players close to their same experience level, not to mention veteran starters, for a longer period of time before getting established. Still, in other cases these guys kick around different leagues before succeeding in the NFL.
Quarterbacks Warren Moon (Canadian Football League), Jeff Garcia (CFL), Kurt Warner (Arena Football League and NFL Europe), defensive end/outside linebacker Cameron Wake (CFL) and feature back Fred Jackson (National Indoor Football League, United Indoor Football and NFL Europe) are starring examples of this refrain.
Three big rookie surprises in the NFL during 2011 all hailed from the fifth round in Houston Texans quarterback T.J. Yates (University of North Carolina), Oakland Raiders wide receiver Denarius Moore (University of Tennessee) and Seattle Seahawks cornerback Richard Sherman (Stanford University).
Yates, in particular, rode a tremendous roller coaster from draft sleeper to No. 3 on the depth chart before assuming the reins under center for the Texans down the stretch and into the playoffs, advancing to a tough loss on the road in Baltimore in the divisional round.
This slideshow examines a group of 2012 rookie prospects who are likely to fall onto the draft's third day or beyond it entirely but who I believe have the upside to surprise in the league and enjoy quality careers.