He was injured in a non-contact drill. And it was only September of his freshman year, 2003.
Three years removed from the injury, Kinlaw has returned. With the possibility of Austin Scott redshirting, he has moved into the backup tailback gig behind senior Tony Hunt. Kinlaw responded with a strong showing against Youngstown State last weekend, tallying 86 yards on six carries and nearly breaking a kickoff return for a score.
He is not a bruiser, not like Hunt. At 5-foot 9, 193 pounds, he's a slasher, a back his teammates regularly describe as somebody who can split the seams through a secondary on any play.
He's one of the quickest guys on the team, Hunt said. He's a home run threat every time.
Considering the quickness on the team, from A.J. Wallace to Derrick Williams, Justin King to Knowledge Timmons, that's a heck of a compliment bestowed on the guy who many felt would collect garbage duty on the third string this fall.
But without the knees he's nothing; he's just another kid on campus.
The knees are the lifeblood for a runner who tries to go around defenders, not over them. And it was difficult for him to trust his legs after a non-contact injury.
Mentally, that was the toughest part, Kinlaw said. The hardest part was knowing I could make the cuts without getting hurt.
An ACL injury is a frustrating one. It takes time to heal and for Kinlaw it took him about a year to feel the same as he did before he blew out his knee. But he exudes confidence now, and Saturday he showed why as he put up the best numbers of his career.
Not only did he run well as a tailback in Penn State's 37-3 win over Youngstown State, he also returned one kickoff 50 yards to midfield. It was the Nittany Lions' best return of the day.
Rodney's more of a breakaway, fast, quick, slash-type back, center A.Q. Shipley said. A one-two combo between [Hunt and Kinlaw] - they can present different challenges to different defenses.
Saturday, Penn State rushed for 389 yards, its most since 2002, with Hunt's 143 leading the team but Kinlaw averaging 14.3 yards per carry.
Whether the output catapults him into a larger role starting this week at No. 1 Ohio State, nobody knows for sure. Kinlaw insists he's happy with however many touches he gets, regularly saying that he just wants to get onto the field.
Kinlaw set a tone for the 2006 season last spring, when he saw plenty of first-team snaps after Scott and Hunt were slowed by injuries.
The ability was always there, Kinlaw said. I got a chance to show them my potential.