By David McDonnell Erik ten Hag has been given no assurance he will remain as Manchester United boss beyond this summer. The pressure on Ten Hag intensified with Sunday’s 3-1 derby defeat at Manchester City, which has left United in sixth spot, 11 points behind fourth-placed Aston Villa, with 11 games left. Ten Hag’s future depends on whether he is able to secure Champions League football for next season, but with that looking increasingly unlikely, candidates for the United job have emerged. Representatives of managers are understood to have put their clients in the frame for the Old Trafford…