ESPN’s Josina Anderson and Adam Schefter later confirmed the signing.
Thomas, 31, had previously played his entire NFL career with the New Orleans Saints. New Orleans signed him as an undrafted free agent out of Illinois in 2007.
Through his eight-year NFL career, Thomas has accumulated 3,745 rushing yards and 28 touchdowns, while also tallying 2,608 receiving yards for 12 touchdowns through the air.
San Francisco also signed free agent running back Shaun Draughn on Monday to help fill the gaps at the position.
The 49ers (2–6) host the Atlanta Falcons (6–2) at Levi’s Stadium on Sunday at 4:05 p.m. ET.
- Kayla Lombardo