The news is setting in.

At the age of 30, seven-time Pro Bowl linebacker Joe Staley plans to announce his retirement from the San Francisco 49ers.

Willis' decision was revealed to the football world on Tuesday. It's a challenging moment for die-hard fans of the 49ers and their star inside linebacker.

The retirement also allows those very same fans an opportunity to reflect on Willis' contributions to the Bay Area and San Francisco's football team.

Many have shared their thoughts on social media. As for us here at 49ers.com, we offer you a list memories from one of the greatest defenders to ever don a red and gold uniform.

Here are 10 things you need to know about the fierce linebacker from Bruceton, Tenn.

1. His debut.

Sept. 10, 2007 on a Monday night at Candlestick Park. That was the first time Willis ever wore a 49ers uniform in a regular season game. Willis led San Francisco's defense with 11 tackles (nine solo) in a 20-17 divisional victory over the Arizona Cardinals. It was the first of 10 double-digit tackle performances from the impact defender that season. Willis' open-field hit on then Cardinals quarterback Matt Leinart was a highlight of the night. He finished the year with 226 tackles, according to the count of 49ers coaches, and won his first of two Bill Walsh awards as San Francisco's Most Valuable Player. The Elias Sports Bureau credited Willis, the Associated Press' Defensive Rookie of the Year, with 174 tackles, which were 30 more than any other player in the NFL that season.

2. His accomplishments.

Although Willis is walking away from the game, he does so with a laundry list of accolades to his name: seven Pro Bowls and six All-Pro selections, including five as a first-team All-Pro. Willis became the first player in 49ers history to reach the Pro Bowl in his first seven seasons. He bested the record of four Pro Bowl nods held by Hall of Fame defensive back Ronnie Lott. In other impressive statistical feats, the well-rounded interior defender was the only player in the NFL to record 20 sacks (20.5), 15 forced fumbles (16) and eight interceptions (8) since the start of the 2007 season.  In 112 starts, Willis recorded 10-or-more tackles in 70 games. He posted 20-plus tackles on five occasions. He tied his career-high for 22 tackles in the final game ever played at Candlestick Park on Dec. 23, 2013.

3. His leadership.

The pregame speeches, who could forget them? Certainly not his teammates. One of the staples of any 49ers game from the past eight seasons was the sight of number 52 giving an inspired talk to his teammates near the 50-yard line. Willis offered inspired words. The soft-spoken player changed his tone when ordering his teammates to "fear no team and fear no man!" before a road win over the New England Patriots in 2012. The same player who smiled at inquiring reporters during the week, looked at his 52 teammates before the closing of "The 'Stick" to tell them, "Let's make history tonight, men!" Willis' words and fiery demeanor will not be forgotten.

4. His charitable work.

This is probably the most underrated aspect of Willis' reputation. On the field, he was feared. Opposing offensive coordinators would find ways to run away from him, or devise plans to send double-team blocks his way. Away from the gridiron, however, Willis was one of the most approachable people to ever wear a 49ers uniform. He was accountable in the community, a big emphasis of the York family, who takes pride in giving back to the Bay Area's youth. One example of Willis' kindness was his willingness to visit children's hospitals with his fellow linebackers. It was a tradition brought over to the 49ers when veteran Takeo Spikes joined the team in 2009. Willis continued the practice last offseason with Chris Borland, who figures to be his likely replacement next to NaVorro Bowman.

5. His personality.

We touched on this in the first four sub-topics, but Willis really was a unique guy. He liked to sing R&B in the locker room (mostly when the coast was clear). He was friendly with the staff, which included everyone from full-time employees to part-time interns. Willis would always say "Yes, sir," or "Yes, ma'am," when speaking to reporters. He would listen to their questions and do his best to answer them honestly without giving away valuable information. He never disrespected opponents; he praised them. He was a class-act on and off the field.

6. His benevolence.
You're probably starting to see a theme with this article. Willis did many things that endeared him to the 49ers Faithful. He also did something that was very touching to this writer. I have two quick stories about Willis' kindness to share. When I wrote a Gameday magazine feature on Willis in 2013, he sought me out a week later with a signed cover. That meant a lot. But what meant more was how he treated a member of my family, someone he never even met. When my 9-year-old nephew wrote that Willis was his hero as part of his class assignment, I casually brought it up to Pat because I thought it would make him smile. It did. But what happened next, I didn't foresee. Pat asked me to film a video for my nephew. Pat looked directly into my cell phone and gave a personalized message to my nephew. He said, "Thank you, Noah," at the end. I can't tell you how much something like that meant to my family. Pat, no question, is a real good dude.

8. His mentoring.
Leadership doesn't mean much if nobody follows. Although Willis is moving on from the 49ers, he leaves an enduring legacy. He helped turn the franchise around from an eight-year playoff drought to yearly Super Bowl aspirations. He also helped revitalize San Francisco's defensive reputation. And with that stellar defensive play, the team's young linebackers had the perfect player to emulate. The 49ers are in good hands in the linebacker department (Bowman, Borland, Michael Wilhoite, Nick Moody), because they followed 52's lead. They've all credited Willis for helping their individual development. And while they won't be able to watch Willis' footwork, or block-shedding ability, they can always turn on the tape to see him flying around the field and inspiring his teammates with his game-changing motor.

9. His hobby of choice.

To know Willis is to know his passion for fishing. The self-described "Country Boy," has always maintained his southern roots in Northern California. If you follow him on social media, chances are you've seen him reel in a large fish. You've also noticed the ear-to-ear grin on his face. Willis' fishing passion ramped up in 2012 when Randy Moss, another avid fisherman, was signed to a one-year contract. Willis fished with another notable athlete, former San Jose Sharks forward Owen Nolan, who happened to be a neighbor of the linebacker. A lot of people apply the phrase "gone fishing" when retirement is on the table, and with Willis, that's not a bad thing for him. He certainly enjoys it.10. His future.
This is the section that needs to be revisited. We don't know what's next for Willis just yet. We know he wants to move on from professional football. We've also heard reports that Willis wants to give back to the youth. When you know him, and where he came from, it makes sense. Pat's huge heart and generosity will live on long past his football career.

Farewell, Patrick.

Thank you.