Patrick Willis was one of the NFL’s best linebackers during his prime. The San Francisco 49ers middle linebacker called it quits at age 29.

Tom Brady, as we all know, still is going strong at age 41, preparing for his ninth Super Bowl. And the New England Patriots quarterback wants to play until he’s 45.

To Willis, that’s just insanity.

“To me, that’s crazy,” Willis told Cam Inman of The Mercury News. “Mentally, when I finished, I felt so old and tired. Holy (expletive), how can guys play forever like that, all those years?”

Brady and the Patriots are gearing up to battle the Los Angeles Rams and young quarterback Jared Goff. The game is chock-full of symmetry. The Patriots’ dynasty began when plucky New England beat the star-studded St. Louis Rams in Super Bowl XXXVI 17 years ago, and now the roles have reversed. The young quarterback, Goff, and up-and-coming head coach, Sean McVay, now reside on the Rams’ sideline, while Brady, Bill Belichick and the Patriots are trying to win a sixth Super Bowl title.

Willis, who retired suddenly in 2015, respects Brady’s fire but wonders why the quarterback still wants to keep playing.

“Goff is a young buck, then Brady is an OG and the sun is setting on him,” Willis said. “I heard he’s playing until he’s 45 and I’m like, ‘Holy (cow), what are you still chasing? What are you after? What’s the high?’ To each his own.”

Brady has publicly stated he still loves everything about the grind of playing football. He loves preparing, training, hanging out with his teammates and pursuing championships.

That’s why Brady already has stated there’s “zero” chance he will retire after Super Bowl LIII and why he plans to keep playing until that flame no longer burns.

Thumbnail photo via Kyle Terada/USA TODAY Sports Images