Bernard was released by the Cincinnati Bengals last week after eight seasons with the team. He reached an agreement on a one-year deal with the Buccaneers on Monday.
The 49ers would presumably be looking for additional depth behind Raheem Mostert as Tevin Coleman signed with the New York Jets this offseason and Jerick McKinnon remains a free agent. Jeff Wilson Jr. remains on the roster as the backup currently with JaMycal Hasty and Austin Walter as depth options.
The Seahawks re-signed Chris Carson to a two-year deal this offseason and former first-round pick Rashaad Penny returns after missing most of last season while recovering from a torn ACL. Former draft picks Travis Homer and DeeJay Dallas remain on the roster and Alex Collins was re-signed this offseason as well. Their interest in another running back would seemingly convey a lack of total trust in the options behind Carson, or at the very least a player to fill a specific role they feel is lacking in their other options currently.
The report notes that Bernard heard from Pete Carroll and Russell Wilson about joining the team in Seattle, which would be another indication Carroll and Wilson have fully committed to their relationship together continuing for at least one more season as well.