Borussia Dortmund defender Mats Hummels has told Manchester United that he is open to a summer move but only if they qualify for the Champions League, [football] direct news understands.The German centre-back has been linked with a summer move to Premier League side Man United in recent weeks as manager David Moyes looks to re-build his squad for next season and replace the departing Nemanja Vidic.googletag.cmd.push(function() { googletag.display(“div-gpt-ad-1389116196215-0”); });Vidic is all but certainly moving to Italian side Inter Milan and that has prompted the English side to show interest in Hummels.The 25-year-old has struggled with fitness this season and has played just 14 games in the Bundesliga but that has not stopped United and another side – Barcelona, from showing interest.However, [FDN] understands that Hummels has told United officials that he will only join them if they qualify for the Champions League.United currently sit sixth, eleven points behind fourth place Liverpool.