49ers' Samuel expected to miss 1-2 weeks with groin strain
Shanahan added that linebacker Fred Warner will also miss Week 13 due to a hamstring injury, though he's hopeful he can return the following week.
Both players were injured in the 49ers' Week 12 win over the Minnesota Vikings.
Samuel has been in the midst of a breakout campaign in his third year. He has flashed as a dual-threat option, recording 1,006 receiving yards and 203 rushing yards for 10 total touchdowns. His 14.9 yards per touch also leads the league.
Brandon Aiyuk could receive more looks with Samuel sidelined. After a slow start to the season, the former 2020 first-round pick has notched 19 receptions for 291 yards over his last four games.
The 6-5 49ers have reeled off three consecutive wins. Their next two opponents are the Seattle Seahawks and Cincinnati Bengals, with both matchups coming on the road.