Tony Gutierrez/Associated Press
According to Rainer Sabin of The Dallas Morning News, the average age of a player on the Cowboys' defensive unit is 25.4.
Sean Lee is out for the season before playing a regular-season down. Anthony Spencer is still recovering from an injury that sidelined him almost all of last season. George Selvie missed the first game of preseason due to a groin injury.
New defensive coordinator Rod Marinelli once again finds himself trying to put together the puzzle that is Dallas' defensive depth chart. Defensive end Tyrone Crawford has faith in his former defensive line coach's ability to put together a decent picture, though.
"He's Master Splinter. Definitely," Crawford told Sabin, comparing his coach to the leader of the Teenage Mutant Ninja Turtles.
Marinelli helped turn Selvie from a journeyman into the team's best pass-rusher last season. He found linebackers to fill in for the injuries sustained by Justin Durant, Lee and Bruce Carter that same year.
As a defensive coach, Marinelli has put together a successful track record when looking at his time in Chicago and Tampa Bay. He'll need to use all he has learned through the years to fill out this young and inexperienced squad.
Probable starting defensive linemen Henry Melton and Jeremy Mincey are new to Dallas. Others like Crawford and Nick Hayden have little starting experience to their credit.
Marinelli still has some time to decide who works best where, but he has a jigsaw-sized workload ahead of him.
All statistics were retrieved from NFL.com unless otherwise sourced. Alex Hall is a Dallas Cowboys featured columnist for Bleacher Report. Follow him on Twitter @AlexKHall.