49ers' Raheem Mostert's 3-Year-Old Son Taken to Hospital with Severe COVID Symptoms

San Francisco 49ers running back Raheem Mostert said his three-year-old son, Gunnar, has returned home after being taken to the hospital Wednesday because of severe COVID-19 symptoms, per TMZ Sports.

Mostert's wife, Devon, posted a picture of Gunnar being transported to the hospital with a 103.5-degree temperature and other symptoms along with a plea to take the disease seriously. The Niners rusher echoed that sentiment in his own post.

"I could say a lot, but I'm going to keep this short because my family gets 100% of my time right now," Mostert wrote. "Take COVID seriously! It's not a joke!!"

The couple has another son, 1-year-old Neeko, and Devon announced on Christmas Eve they're expecting a third son in 2022.

Mostert was among the first American athletes to show concern about COVID-19 when he canceled a scheduled autograph signing in early March 2020, even before U.S.-based sports leagues began to postpone their seasons because of the virus.

The Florida native told Josh Dubow of the Associated Press in May 2020 that Devon raised concerns because she was pregnant with Neeko at the time.

"She has actually cried a couple of times just because she wants to make sure not only myself but those 90 guys that are in the locker room are going to all be safe, and their families as well," Mostert said about his wife's concerns ahead of the 2020 season.

Mostert was the breakout star of the 2019 playoffs as the Niners advanced to the Super Bowl. His standout stretch was highlighted by a 220-yard, four-touchdown rushing performance against the Green Bay Packers in the NFC Championship Game.

The 29-year-old Purdue product's last two seasons have been derailed by injuries, though. He landed on injured reserve after the team's Week 1 win over the Detroit Lions this season with a knee injury.

He announced the decision to undergo season-ending surgery in September.