Mariani has nice size and great versatility. He's not the quickest kid on the field, but he does run a 40-yard dash in the sub-4.5 range, which makes him a decent bet to fill in as a slot receiver for any team in the league.
In his senior season, he grabbed 81 catches for more than 1,400 yards and 14 scores. That's more than 18 yards per catch on the season.
Sure, he played at a smaller school against lesser competition than, say, a Jordan Shipley of Texas. But last I checked, the ability to run and catch has more to do with a player's success than the school the player reps—just ask Terrell Owens.
Mariani has playmaking talent, and in the early going, special teams value as well. That makes him a legitimate prospect for any number of NFL teams.
http://bleacherreport.com/articles/352535-2010-nfl-draft-10-deep-offensive-sleepers-you-may-not-have-heard-about#page/1
Matt Nichols also is one of the 10.