There are suggestions of a loan move for the City defender but there's no official word yet.
Barker played for the reserves at Postmouth on Monday. He along with Rhys Weston and Jeff Whitley, who also both played at Pompey, are the players Dave Jones could move on to free up wages space for new signings.
Released Willie Boland is training with Grimsby Town.
One time target Scott Carson has signed a season long loan deal at Charlton.