San Francisco 49ers

Former 49er Aldon Smith’s brain will be donated to check for CTE. What we know

49ers outside linebacker Aldon Smith celebrates a sack of New York Giants quarterback Eli Manning during the NFC championship game at Candlestick Park on Jan. 22, 2012.
49ers outside linebacker Aldon Smith celebrates a sack of New York Giants quarterback Eli Manning during the NFC championship game at Candlestick Park on Jan. 22, 2012. Sacramento Bee file
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  • Aldon Smith’s brain will be donated to a Boston research center for CTE study.
  • Medical experts will examine whether repetitive brain injuries contributed to his death.
  • Smith died at 36 just after delivering pizzas to a homeless charity; cause undetermined.

Former San Francisco 49ers defensive star Aldon Smith’s brain will be donated to a research center in Boston, where medical experts will investigate whether CTE or repetitive brain injuries played a part in his sudden death at 36, lawyers for Smith’s family said Tuesday.

A cause of death has not been determined since the All-Pro linebacker died Saturday, just after delivering pizzas to a homeless charity in the Bay Area, according to a statement released by the lawyers.

The lawyers said they were investigating “all aspects” that could have caused Smith’s death, noting CTE specifically due to the “numerous” concussions he suffered in his career.

“As with anyone who dies so suddenly at such a young age, we understand that there is a great deal of interest in and speculation about Aldon Smith’s passing,” said Harry Daniels, Bakari Sellers and Wayne Kendall, the family’s attorneys, in the statement. “We intend to get to the bottom of it.”

What is CTE?

Chronic traumatic encephalopathy, commonly known as CTE, is a degenerative brain disease found in those that experience a history of repetitive brain trauma, like tackling contact in football, according to the Concussion & CTE Foundation. The disease leads to malfunctions that kill brain cells.

CTE is most commonly found in contact sport athletes and military veterans.

There is currently no way to diagnose CTE while a patient is alive, according to the foundation, so it is unclear the extent to which the disease impacts NFL players.

According to the Mayo Clinic, CTE symptoms can include the following, though no specific symptoms have been clearly linked to the disease:

  • Trouble thinking
  • Memory loss
  • Difficulty planning, organizing and carrying out tasks
  • Impulsive behavior
  • Aggression
  • Depression
  • Emotional instability
  • Substance misuse
  • Suicidal thoughts or actions
  • Trouble walking and balancing
  • Loss of control of movements

‘I’ve definitely had better days’

In an interview posted on the YouTube channel Laced Up just four days before his death, Smith said he was struggling to come to terms with parts of his life. Having recently moved back the Bay Area, Smith said he was grateful for the warm reception but wasn’t sure if he was ready to be back.

“I’ve definitely had better days,” Smith told Tee Maultsby on the barber’s show. “It’s something I think I’ve been dealing with my whole life, and I’m just struggling with accepting how it’s playing out right now.”

Days later, Smith’s friend Amir Shirazi would find Smith slumped over the front of the passenger seat of his truck just before he was pronounced dead at a hospital.

Shirazi, who called 911 and some of Smith’s friends to the scene, told the San Francisco Chronicle that he was in shock soon after his friend’s death.

“We were joking about life and talking about stuff right before,” Shirazi told the Chronicle. “He was perfectly fine an hour before.”

Shirazi told the Chronicle that Smith had been struggling in the lead-up to his death, bouncing between friends’ houses due to his financial situation and waiting for his NFL pension to begin payouts.

“His only problem, and it’s true with a lot of athletes, is he made a lot of money and they lose control of themselves,” Shirazi told the Chronicle. “You give a bunch of guys in their 20s a lot of money and they lose it.”

Who was Aldon Smith?

After being drafted by the 49ers seventh overall in 2011, Smith put together back-to-back stellar seasons, getting second in Defensive Rookie of the Year in 2011 and being a First-Team All-Pro and Pro Bowl selection in 2012.

In those two seasons alone, Smith amassed 33.5 sacks, 103 tackles, 31 tackles for loss, 56 quarterback hits, five forced fumbles and an interception. The 33.5 sacks are the most ever in an NFL player’s first two seasons.

After 2012, Smith’s career would be heavily impacted by off-the-field issues, only playing in 16 games in one more season before he officially announced his retirement in 2023 after serving six months in jail for a 2021 DUI incident.

The Niners released Smith in August 2015 after his fifth arrest in three years, this time a suspected DUI hit-and-run. While Smith was able to sign with the then-Oakland Raiders and play in nine games, he was suspended for a year relating to the DUI incident, and the former All-Pro missed the entirety of the 2016 through 2019 seasons due to suspensions.

While Smith successfully appealed his indefinite NFL suspension in 2020 to play for the Dallas Cowboys, that would be his final season in the league. Starting in all 16 games for the first time since 2012, Smith had five sacks, 48 tackles and a fumble returned for a touchdown.

Smith then signed with the Seattle Seahawks on a one-year deal, before the St. Bernard Parish Sheriff’s Office in Louisiana issued an arrest warrant for Smith on a second-degree battery charge. The Seahawks released him before the start of the 2021 season.

‘Just tragic, no words’

The 49ers and Raiders released statements soon after Smith’s death Saturday, honoring his legacy and time with the teams, with the Niners calling his death “sudden and tragic.”

Smith had reportedly visited Levi’s Stadium to speak to new 49ers rookies as soon as one week before his death.

“Aldon’s undeniable talent and sheer dominance on the field were on display from the moment he joined our organization,” the statement said. “Beyond his excellence as a player, Aldon will be remembered for his infectious smile that lit up every room he walked into.”

Jim Harbaugh, who was the head coach of the 49ers for four of Smith’s seasons with the team, said Smith was “much loved by all,” according to ESPN’s Kris Rhim.

“Just tragic, no words,” Harbaugh said. “There’s times I thought he was hard on himself, but mostly always a wonderful person to others.”

Multiple 49er teammates have posted statements online about Smith’s death, including former Niners running back and kick returner Anthony Dixon. Dixon was reportedly among those called by Shirazi after he found Smith hunched over in the truck.

“I wish I could’ve did more to help him and pray to God that he doesn’t have to hurt anymore,” Dixon said in the caption of an Instagram post about Smith’s death. “I love you bro, I hope you doing good and I’m glad I got to see you before you left.”

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Sean Campbell
The Sacramento Bee
Sean Campbell is a 2025 and 2026 summer reporting intern covering sports and news at The Sacramento Bee. Campbell is studying journalism at USC and serves as a news editor at the student-run Daily Trojan. He previously covered sports for the Davis Enterprise.
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