The 49ers signed Cooks from the practice squad to the active roster Thursday, Nick Wagoner of ESPN.com reports.
Cooks spent a little more than a week on San Francisco's practice squad before joining a position group that currently has two injured players on the active roster and four on injured reserve. He split time between the Saints and Bills in 2025, combining for a 24-279-0 line on 36 targets in 15 regular-season games.