San Francisco 49ers linebacker Patrick Willis (52) pursues during an NFL game against the Seattle Seahawks, Sept. 30, 2007 in San Francisco. (AP Photo/ Greg Trott)

San Francisco 49ers linebacker Patrick Willis (52) returns an interception 23 yards for a touchdown during an NFL game against the St. Louis Rams, Oct. 4, 2009 in Oakland. The 49ers won the game, 35-0. (AP Photo/Greg Trott)

Tennessee Titans running back Chris Johnson (28) gets tackled by diving San Francisco 49ers linebacker Patrick Willis (52) after catching a pass good for 16 yards and first and goal during the NFL football game against the San Francisco 49ers, November 8, 2009 in San Francisco, California. The Titans won the game 34-27. (AP Photo/Paul Spinelli)

SAN FRANCISCO - OCTOBER 10: Patrick Willis #52 of the San Francisco 49ers comes out of the locker room before the game against the Philadelphia Eagles at Candlestick Park on October 10, 2010 in San Francisco, California. (AP Photo/Tom Hauck)

San Francisco 49ers inside linebacker Patrick Willis (52) runs off field high giving fans during an NFL football game between the San Francisco 49ers and the Indianapolis Colts game Sunday, Sept. 22, 2013 in San Francisco, CA. (AP Photo/Tom Hauck)

San Francisco 49ers linebacker Patrick Willis (52) rests during an NFL football game against the Arizona Cardinals on Sunday, Sept. 21, 2014, in Glendale, Az. The Cardinals won the game, 23-14. (AP Photo/Greg Trott)

San Francisco 49ers inside linebacker Patrick Willis (52) is seen in action during an NFL football game against the Chicago Bears at Levi's Stadium on Sunday, September 14, 2014 in Santa Clara, California. Chicago won 28-20. (AP Photo/Aaron M. Sprecher)

In this Nov. 10, 2013 photo, San Francisco 49ers linebacker Patrick Willis (52) is introduced before an NFL football game against the Carolina Panthers in San Francisco. (AP Photo/Marcio Jose Sanchez)

San Francisco 49ers linebacker Patrick Willis talks with reporters during a news conference on Wednesday, Jan. 30, 2013, in New Orleans. The 49ers are scheduled to play the Baltimore Ravens in the NFL Super Bowl XLVII football game on Feb. 3. (AP Photo/Mark Humphrey)

San Francisco 49ers inside linebacker Patrick Willis (52) runs onto field during an NFL football game between the San Francisco 49ers and the Indianapolis Colts game Sunday, Sept. 22, 2013 in San Francisco, CA. (AP Photo/Tom Hauck)

San Francisco 49ers' Patrick Willis reacts during player introductions before an NFL football game against the Seattle Seahawks, Sunday, Dec. 8, 2013, in San Francisco. (AP Photo/Marcio Jose Sanchez)

San Francisco 49ers linebacker Patrick Willis (52) is introduced before an NFL football game against the Carolina Panthers in San Francisco, Sunday, Nov. 10, 2013. (AP Photo/Marcio Jose Sanchez)

San Francisco 49ers linebacker Patrick Willis (52) celebrates after the 49ers beat the Kansas City Chiefs 22-17 in an NFL football game in Santa Clara, Calif., Sunday, Oct. 5, 2014. (AP Photo/Marcio Jose Sanchez)

San Francisco 49ers linebacker Patrick Willis (52) watches from the sideline during an NFL preseason game against the San Diego Chargers in Levi Stadium in Santa Clara, California on Sunday, August 24, 2014. The 49ers defeated the Chargers 21-7. (AP Photo/Kevin Terrell)

San Francisco 49ers Patrick Willis (52) and Donte Whitner celebrate after teammate NaVorro Bowman made an 89-yard touchdown in the fourth quarter of an NFL football game against the Atlanta Falcons in San Francisco, Monday, Dec. 23, 2013. (AP Photo/Marcio Jose Sanchez)

San Francisco 49ers linebacker Patrick Willis (52) before an NFL football game against the Atlanta Falcons in San Francisco, Monday, Dec. 23, 2013. (AP Photo/Marcio Jose Sanchez)

San Francisco 49ers inside linebacker Patrick Willis (52) gets into a defensive posture while warming up before the NFC Divisional Playoff NFL football game against the Carolina Panthers on Sunday, Jan. 12, 2014 in Charlotte, N.C. The 49ers won the game 23-10. (AP Photo/Paul Spinelli)

Green Bay Packers wide receiver Greg Jennings (85) is tackled by San Francisco 49ers linebacker Patrick Willis (52) during an NFL football game in Green Bay, Wisconsin Saturday, Sept. 9, 2012. (AP Photo/Tom Hauck)

San Francisco 49ers linebacker Patrick Willis (52) tackles Atlanta Falcons wide receiver Julio Jones (11) during the NFL football NFC Championship game Sunday, Jan. 20, 2013, in Atlanta. The 49ers won 28-24. (AP Photo/David Stluka)

San Francisco 49ers inside linebacker Patrick Willis (52) during an NFL regular season game against the Arizona Cardinals on Sunday, Oct. 13, 2013 in San Francisco. The 49ers won the game, 32-20. (AP Photo/Ric Tapia)

Arizona Cardinals wide receiver Larry Fitzgerald (11) is tackled by San Francisco 49ers inside linebacker Patrick Willis (52) during the first half of an NFL football game, Sunday, Dec. 29, 2013, in Glendale, Ariz. (AP Photo/Matt York)

San Francisco 49ers inside linebacker Patrick Willis #52 before the game against the Kansas City Chiefs at Levi's Stadium in Santa Clara, Calif. on Sunday, Oct. 5, 2014. (AP Photo/Michael Zito)