Still green when it comes to experience after switching from the defensive to the offensive line after the 2011 season to help build depth, Costigan still started nine games last season, and did most of it season on one healthy leg.
Dislocating his right knee cap in the first Nebraska game, Costigan missed the next week, but started seven of the team's final eight games before having microfracture surgery to repair substantial cartilage loss shortly after the Rose Bowl.
In retrospect, he called it one of the hardest things he's ever done, as he basically played the position using his upper-body strength.
"I would never say I was close to 100 percent," said Costigan. "It's really hard to improve your technique and stuff when you are playing on one leg and you have to be straight legged. I try to be an effort guy, but it's hard to get that low pad level that you need to form your technique properly. It was frustrated, but I am happy I still got to play."
So with two starters departing, a new offense being installed and the third offensive line coach in two seasons in the mix, Costigan wanted nothing more than to grind in the trenches through spring football. Imagine his disappointment when all he could do in the spring was ride a stationary bike on the sidelines.
"It's extremely frustrating, knowing you aren't allowed to do anything but try to recover while everyone else is getting better," said Costigan. "One of the worst things was we were going against a new defense with a tight front. The experience of going against that and getting all the reps would have been useful for me."
It's why Costigan called his first few weeks of camp "streaky," trying to knock off the rust and change from a guy who used to get by on his strength to one that got by on his technique.
"I just tried to learn as much as I can from coach Woods in meetings and stuff like that, trying to get it translate as soon as possible," said Costigan. "Coach Woods is really a technician, so he's really helping me with everything I need to get done."
Serious injuries have a funny way of working out for Costigan. Suffering a serious third-degree ankle sprain before the summer of his senior year of high school, Costigan couldn't go through the college camp circuit to try to earn scholarship offers. Former offensive line coach Bob Bostad stumbled upon him and gave him a full scholarship offer right before signing day.
Now he's back with the first-team offense, working on building chemistry with his teammates on two healthy legs.
"We have a tight-knit group on the offensive line," said Costigan. "It's going to be fun to see what we can do together."