What happened: San Francisco lost Ricky Pearsall, De'Zhaun Stribling and Demarcus Robinson to injuries early this season. Mike Evans is being managed this week with a hip injury. Cooks is signing with the practice squad initially to get up to speed for games.
Why it matters: The cluster of absences stresses depth during the regular season. Cooks is a 13th-year former first-round pick.
By the numbers: Cooks sits 189 yards short of 10,000 career receiving yards.
What to watch: Watch practice reports for Evans and whether Cooks is elevated to the active roster.