The San Francisco 49ers have announced that linebacker Aldon Smith has been activated to their 53-man roster.

The 25-year-old was suspended for nine games by the NFL for violating their policy on personal conduct and substance abuse for misdemeanours committed in the off-season.

However, Smith has served his ban after being reinstated on Tuesday, and is now eligible to play against the New York Giants in his side's week-11 match.

Rookie safety Jimmie Ward was placed on injured reserve to make room for Smith on the roster after he sustained a foot injury in Jim Harbaugh's side's narrow win over the New Orleans Saints.

Ward recorded 20 tackles for the 49ers in eight matches this season.