LONDON: Sunderland have signed former Newcastle goalkeeper Steve Harper until the end of the season, the Premier League strugglers confirmed on Friday. Harper will provide back up to first choice keeper Vito Mannone and help mentor promising young reserve Jordan Pickford. The 40-year-old, who was a free agent after leaving Hull at the end of last season, made 199 appearances for Sunderland’s bitter rivals Newcastle. Harper had been working as a coach at Middlesbrough’s academy and as a radio pundit before Black Cats boss Sam Allardyce approached him following Costel Pantilimon’s departure to Watford earlier this week.