Hankins, an affable junior from Detroit, was a starter the past two seasons for the Buckeyes. He was named the team's top defensive lineman in 2011 and earned All-Big Ten honors this past season when he recorded 55 tackles, including four for loss.
He had 67 tackles, including 11 for loss, as a sophomore.
"I will always be grateful for the family I have gained here at Ohio State," said Hankins, who was a three-star recruit at Detroit Southeastern when he signed with then-head coach Jim Tressel and defensive line coach Jim Heacock.
He now leaves early an Ohio State squad that will lost all four starters from the 2012 season but has been stocked with young, highly recruited defensive linemen the past two recruiting seasons by current head coach Urban Meyer and defensive line coach Mike Vrabel.
Seniors Nathan Williams, John Simon and Garrett Goebel are set to graduate, but highly recruited prospects Adolphus Washington, Tommy Schutt and Noah Spence all played significant minutes last season as true freshmen. The 2013 recruiting class includes six verbal commits from defensive linemen, including five-star prospect Joey Bosa and four-stars Tyquan Lewis, Donovan Munger, Michael Hill and Billy Price and three-star Tracy Sprinkle.
"I want to thank Coach Meyer, Coach Vrabel and strength coach (Mickey) Marotti for bringing the best out of me as a football player and person, and for their constant support. I also want to thank Coach Tressel and Coach Heacock for recruiting me and giving me an opportunity to be a part of this great school and great program."
Meyer said in a statement he enjoyed coaching Hankins during the past year.
"His hard work on and off the field has given him an opportunity to move on to the next level," Meyer said. "The coaching staff and I wish him all the best."
Hankins is the first Ohio State player to leave early for the league's regular April draft since Thaddeus Gibson following the 2009 season. He was a fourth-round pick of the Pittsburgh Steelers in the 2010 draft.
Ohio State had an underclassmen selected in every April draft from 2004-10 but none the past two years, a streak Hankins is likely to snap as he has been projected as a first-round pick by many sources.
"My three years at The Ohio State University have provided amazing experiences for me, and they are years I will never forget or take for granted," Hankins said. "My plans are to return to finish my degree and to continue to be a part of this brotherhood of Buckeyes. I am so appreciative for the support I have received from my teammates, the coaching staff and administrators at Ohio State, and of course, my family."
Fifteen Buckeyes who played for Tressel have been drafted as underclassmen, including quarterback Terrelle Pryor, who was a supplemental pick in 2011 after leaving school in the midst of an NCAA investigation earlier that summer.