49ers face QB uncertainty vs. Jaguars as Purdy and Jones both injured, with Martinez as untested backup.

The San Francisco 49ers are dealing with quarterback uncertainty ahead of their Week 4 game against the Jacksonville Jaguars, as both Brock Purdy and Mac Jones are injured. Purdy, who missed two games with a toe injury, returned to practice but remains limited, while Jones aggravated a knee issue during the win over Arizona. Both are expected to be limited in practice, raising doubts about their availability. Third-string quarterback Adrian Martinez, with no NFL experience, is the backup. Purdy has a strong career record with the 49ers, while Jones has shown effectiveness in two starts this season. Wide receiver Ricky Pearsall is sidelined with knee discomfort, and Jauan Jennings is out due to ankle and shoulder injuries. The team is managing multiple injuries ahead of a pivotal game.