His tender, size-13 feet — "12 1/2 when they're bent" — can no longer handle the grind of NFL practices let alone the demands of game day.
Willis announced Tuesday he will retire after his 2014 season was cut short by a toe injury that required surgery and sore feet that make everything more of a challenge.
"In my head, I'm already a Hall of Famer," Willis said. "I am leaving this with closure. I'm happy today, more happy today than the day I was drafted."
San Francisco is losing its defensive captain and locker room leader, the player who often addressed the team before games with inspirational pep talks.
Willis isn't saying exactly what's next, perhaps a vacation, some speaking gigs, a day of fishing, slow mornings with a cup of coffee instead of an intense workout.
"I have no regrets. I've had the most amazing eight years of football of my life. I am so humbled to have had this opportunity. I've been so humbled to have played this game.
Willis and friend NaVorro Bowman had made up one of the best 1-2 linebacker punches in the NFL until both missed time last season, the entire season for Bowman as he recovered from reconstructive knee surgery.
The 30-year-old Willis was sidelined with a strained muscle in his left big toe. He was placed on the season-ending injured reserve Nov. 11 after getting hurt in the third quarter at St. Louis on Oct. 13.
"These feet, boy, boy, boy, I've made no excuses," said Willis, who notes his feet "spoke" to him. "When you don't have no feet, that's what has made me what I am. I no longer have in these feet to give you guys that kind of 'Wow.'"
Late Monday, Willis posted on social media a message that hinted at his farewell from football and included a series of references to bible verses.
"Today is my Future, Past, and Present all in one," he wrote. "It's bigger than me, it always has been and it always will be...I thank you guys for everything, it has been an absolute pleasure....I look forward to the continuation of my journey... I feel full with something that needs to be out, and i just want to share it! Success is only as beautiful as our Consistency! My life is based On a True Concept! I know I'm not the only one!"
Willis had missed six games in his career before this latest injury sidelined him for the final 10 games of 2014 for San Francisco, which struggled to an 8-8 finish without him and missed the playoffs for the first time in four years.
About a half-dozen of his 49ers teammates attended his news conference at Levi's Stadium. Willis, in burgundy pants and a plaid shirt untucked with a loose tie, Willis held a tissue in hand and regularly wiped his eyes.
"He redefined his position," coach Jim Tomsula said. "That's a different man. Pat changed a lot of lives here. Pat will change a lot of lives. ... I've never heard Pat Willis complain."
The NFL Defensive Rookie of the Year in 2007 after being drafted 11th overall out of Mississippi, Willis started 112 games and had 950 tackles with 20 1/2 sacks in eight seasons. Willis also had eight interceptions — two returned for touchdowns — 16 forced fumbles, five fumble recoveries and 53 passes defenced.
"Nothing but respect for Mr @PatrickWillis52 We been thru a lot together," free agent wide receiver Michael Crabtree wrote on Twitter.
As word spread Monday that Willis was contemplating retirement, his former teammates and opponents took to Twitter in tribute to No. 52.
"Still have a chipped tooth from @PatrickWillis52 knocking me out. Congrats on a GREAT career man! Not a nicer guy out there!" quarterback Matt Leinart said.
"Without a doubt the greatest man/leader/friend/teammate @PatrickWillis52 my hero!" wrote former teammate and running back Marcus Lattimore, forced out of the game by his own knee injuries last year.
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