Now the January transfer window has slammed shut, here are four free agents Sunderland should look to sign to fire them into the Premier League at the end of the season. Despite a rocky last couple of months, Michael Beale’s side still has every chance of reaching the top flight at the end of their campaign. The Black Cats sit one point off the play-offs as they look to end a seven-year absence from the top flight. January saw Sunderland hold onto prize assets such as Jobe Bellingham and Jack Clarke despite the latter having plenty of interest from the Premier League. However, there are fears …