Further confirming Willis' toughness, the Sacramento Bee's Matt Barrows reports the seven-time Pro Bowler recently underwent surgery on his left thumb.
Photo evidence from Willis' Instagram account confirms the procedure took place, as the 29-year-old is pictured in celebratory birthday pictures sporting a cast:
As Barrows reports, hand injuries have hampered Willis more than anything in his prolific career to date, with this being the fourth such ailment he's suffered since his junior season in college.
Having only missed six of a possible 112 regular-season games in his seven seasons as a pro, no one can question Willis' will to compete or his status as one of the league's most consistently great inside linebackers.
However severe this injury was, it didn't cause Willis to land on the injury report ahead of the Niners' 23-17 loss to the Seattle Seahawks in the NFC Championship Game. Willis tried to remain positive after the defeat, per 49ers.com's Taylor Price:
We gave everything we had. We fought at the beginning of the season when everyone was picking us to go to the Super Bowl. And when we went through that little slump, everybody started writing us off. We just stayed together and continued to fight. That’s what we did tonight. It’s unfortunate it didn’t go our way.
It's good that Willis should make a rather swift recovery, because his teammate and fellow superstar linebacker NaVorro Bowman tore his ACL and MCL against the Seahawks.
How that impacts the San Francisco defense moving forward remains to be seen, but even if Bowman returns for the start of 2014 as he's expected to, there's no guarantee he'll be the same player he was this season.