Football is a cyclical game.

As the passing game grew and quarterbacks became the foundational pieces for programs and NFL teams, out came the players who made a living getting those players to the turf. That, in turn, created the market for offensive linemen — specifically the left tackle — to protect the quarterback investment. And around and around we go.

But the value for a great defensive lineman is still off the charts. A great interior lineman can make an entire defense better around him as he swallows up blockers and allows his teammates to flow sideline-to-sideline; arguably the best player in college football last year was a defensive tackle: Alabama's Quinnen Williams, who destroyed offenses from the inside out and made plays in the process. And a great edge player who can get to the quarterback? That's even better.

USA TODAY writer Paul Myerberg ranked the top defensive linemen in college football for 2019, and it's a pretty loaded field, one packed with former top recruits and a number of players who have already reached, or started to reach, their massive potential. Myerberg's list then doesn't read as much like a list of players who could be great, but players who already have greatness corralled and are looking for more this season.