"I thought he did a good job," head coach Kyle Shanahan said on Monday of Mack's acclimation to the 49ers offense. "He looked good in practice. He got mainly scout-team reps, but he looked like he'd been around, carried himself the right way, and you can see the skillset that has given him some success in this league."
The 49ers are also signing veteran quarterback Kurt Benkert to the practice squad, per Mike Garafolo of NFL Network. He was one of five quarterbacks who worked out for the team on Tuesday. Starter Trey Lance suffered a broken ankle against Seattle and underwent season-ending surgery on Monday.
Jimmy Garoppolo will serve as the starting quarterback moving forward. The only other quarterback on the roster was seventh-round pick Brock Purdy.
The Atlanta Falcons signed Benkert (6-3, 218) as an undrafted free agent out of Virginia in 2018. He appeared in one game for the Green Bay Packers in 2021 but has yet to make an NFL pass attempt.
San Francisco also cut defensive back Kary Vincent from the practice squad, per the NFL transaction wire.