The 49ers will be without the heart of their defense Sunday against the Seattle Seahawks. After being upgraded to "doubtful" Friday, linebacker Fred Warner officially is inactive with a hamstring strain.
This will be the first time Warner has missed a game in his four-year 49ers career. He played all 16 regular-season games in his first three seasons and has played all 11 of the 49ers' games this season.
Warner, 24, sustained the injury in last week's win against the Minnesota Vikings. In 11 games this season, Warner has 92 tackles, two fumble recoveries and three passes defended.
With running back Trey Sermon placed on injured reserve, JaMycal Hasty is making his return. Hasty has missed six games to ankle injuries this season.
The second-year pro has appeared in five games for the 49ers this year. He has received 13 carries for 48 yards and one touchdown. He also has 13 receptions for 91 yards.
Below are the rest of Sunday's inactives for the 49ers and Seahawks.