The San Francisco 49ers were absolutely ravaged by injuries last season, which played a massive role in their disappointing 6-11. And once again this summer, the 49ers are once again experiencing medical issues. So, what is the reason behind San Francisco's inability to stay healthy? Is there a deeper problem here?

The San Francisco 49ers are bringing back a familiar face under center. According to the Athletic's Matt Barrows, the 49ers are signing quarterback Nate Sudfeld after Sudfeld threw in a wide receiver workout Monday.

Isaac Guerendo and Renardo Green stood out during San Francisco 49ers practice Tuesday as they returned from their respective injuries.

SANTA CLARA – Nate Sudfeld rejoined the 49ers’ quarterback ranks Tuesday, three years after Brock Purdy beat him out as a rookie for the No. 3 role and an unexpected ascent to the franchise’s throne.

Renardo Green and Isaac Guerendo were among those who returned for a practice in which Brock Purdy and Ricky Pearsall continued to connect.

Sudfeld is the fourth quarterback available for Saturday’s preseason finale against the Los Angeles Chargers, with Mac Jones and Carter Bradley still slinging it alongside Purdy. Sudfeld was brought in Monday to throw to three wide receivers who were auditioning as free agents.

San Francisco 49ers cornerback Deommodore Lenoir hilariously explained how his friendship with Chase Lucas has evolved over the years.

Mac Jones will be sidelined for the remainder of the week and for the San Francisco 49ers ’ preseason finale against the Los Angeles Chargers on Saturday. 49ers coach Kyle Shanahan told reporters that Jones suffered a knee sprain and will be unavailable this week due to a knee sprain the quarterback suffered against the Las Vegas Raiders.

The injury list for the San Francisco 49ers went through a bit of a shuffle with a few key players returning from injuries Tuesday while significant questions remain on several others just a week before NFL rosters will be cut to 53 players.