Confirm your age. Are you 18 or over?
Walker, 32, has been with the Celts since 2015 where he previously worked with Boro boss John Deacey, helping them to promotion to National League North last season.
He made his debut for the Seadogs in the 2-0 defeat to Whitby Town last week, but sat out the FA Cup draw against Marske United, with a replay scheduled for tomorrow night.
Keep up-to-date with our exclusive email newsletters.
Digital advertising by Minute Media
© Pitch Hero Ltd 2008-2019
Pitch Hero Ltd Registered in ENGLAND | WF3 1DR | Company Number - 636 1033