Jon Christenson knew the dire circumstances when an Indiana Hoosiers defensive lineman rolled over his leg in 2013.
As the Gophers center lay on the field in pain, the then-sophomore biochemistry major with aspirations to become a doctor told team trainers that he broke the tibia and fibula in his left leg.
"My entire ankle complex hung down," Christenson said. "I knew there was no structure left in my shin."
Christenson, who started as a walk-on from Minnetonka, also knew the distinct challenge to get back on the field. Previous Gophers center Zach Mottla ended his career in July 2013 after a slow recovery from a broken leg at Illinois in 2012.