Trying to put a number on Patrick Willis

It’s hard to put a number on the impact Patrick Willis’ retirement will have on the San Francisco 49ers’ defense. It takes numbers -- with an "s" -- when trying to break it down. And even then, it’s hard to grasp how much the Niners will miss their All-Pro inside linebacker who just turned 30 on Jan. 25.

Consider: According to Elias, no player who debuted since 1970 and was a seven-time Pro Bowler never played a game as a 30-year-old. The previous “record” is five Pro Bowls, and most recently “accomplished” by Al Wilson, who last played in 2006 for the Denver Broncos.

Plus, Willis was named to the Pro Bowl in each of his first seven years, a streak that was broken this past year when he appeared in only six games due to an injury to his left big toe. The only defensive players with longer Pro Bowl streaks to begin their careers since the 1970 merger? Hall of Famers Lawrence Taylor, who went to Hawaii in each of his first 10 years (1981-90), and Derrick Thomas, who did it in his first nine seasons (1989-97).

And Willis is not the only standout Niner on the defensive side of the ball contemplating hanging it up. Defensive lineman Justin Smith is still undecided about returning for a 15th season.

Smith joined the Niners as a free agent from Cincinnati in 2008. Since Willis and "The Cowboy" became teammates in new head coach Jim Tomsula’s second year as the defensive line coach, the 49ers are tied with the Baltimore Ravens for fewest rush yards allowed per attempt per game (3.71), per ESPN Stats & Info.

And since 2009, the Niners have the best scoring defense in the NFL (18.1) while ranking third in yards per game (315.8) and second in Total QBR against (43.7).