ENGLEWOOD, Colo. -- **There's a reason why James Casey's listed position is as a tight end and fullback.
He helps provide seasoned depth behind Owen Daniels and Virgil Green -- something that is even more necessary now that third-round pick Jeff Heuerman is expected to miss the 2015 season because of a torn anterior cruciate ligament suffered in rookie-camp practice last Saturday.
But as the Broncos re-introduce the fullback to their offense, Casey will be busy in the backfield, resuming a role he assumed when he played under Head Coach Gary Kubiak and Offensive Coordinator Rick Dennison for the the Houston Texans, when he was their Week 1 starter at fullback in the 2011 and 2012 seasons before signing with the Philadelphia Eagles in 2013.
"It's been great because any time you come somewhere and you've already been with the coaching staff, it helps out because you know a little bit of the plays," Casey said.
"It's been two years since I've been the system, so I still need to get acclimated back to everything. If anybody asks any questions about certain things that we did in Houston, I'll be able to help out as much as I can with the younger fullbacks and tight ends."
He can help, but even with six previous years in the NFL, Casey is still learning the nuances of fullback, a position that has one of the steepest learning curves of any in the sport.
At some positions, the age of 30 represents the beginning of the downside. But at fullback, it's in the middle of prime years.
At 30, Casey is young enough to be explosive, but seasoned and experienced enough after being a prolific pass catcher at Rice University to have adapted to the demands of the role.
"I think I'm much better suited for the position," Casey said. "The fullback is tough. Early on in my career, I was more of a receiver coming out of college. I kind of had to work my way into working tight end and then I had to learn fullback. I was always learning stuff.
"Now I feel real confident. I've played long enough. I've experienced almost everything that you can see football-wise. A lot of it is just mentality, learning what things are about, how to be physical, how to finish plays and things like that.
Since the 2010 season, every fullback to make the Pro Bowl possessed at least five seasons of experience, with an average of 7.0 years. All but one Pro Bowl fullback was between the ages of 28 and 32.
"I think I'm best suited for it now. I'm older in my career," Casey said. "The physical nature of the game as opposed to running around all over the place, when you're young it's awesome, but as you get a little bit older, you enjoy the blocking, doing your part and whatever you are responsible in the run game."