Overview

• Head coach Kyle Shanahan said Brock Purdy is highly unlikely to start against the Cardinals after three limited practices, though he could dress as the No. 2 or an emergency No. 3.
• Purdy is listed as questionable with toe and non‑throwing shoulder injuries, and roster decisions will determine whether practice‑squad QB Adrian Martinez is elevated for backup duties or signed to the 53.
• Under NFL rules, an emergency third quarterback must be on the active roster, affecting whether the 49ers can use a standard practice‑squad elevation for Martinez.
• San Francisco’s offense is thin up front and at receiver: Ben Bartch went to IR (high‑ankle), Spencer Burford is out (knee), Jordan Watkins is out (calf), Connor Colby is questionable (groin), and Jauan Jennings is questionable (ankle/shoulder).
• Mac Jones, who threw for 279 yards and three touchdowns in last week’s win, will start versus 2‑0 Arizona, while ESPN reports Purdy’s chances to return in Week 4 are described as pretty good.