John Obi Mikel has undergone knee surgery, which has ruled him out of&nbsp; Chelsea&rsquo;s clash with Tottenham Hotspur in the League Cup final on Sunday at Wembley Stadium, writes SL10.ng.<br /><br />Mikel was due to return to action this weekend, but he had to go under the&nbsp; knife in a London hospital after feeling pain on the affected knee.<br /><br />According to the defensive midfielder&rsquo;s adviser,&nbsp; the Nigeria&nbsp; international will require at least four weeks to recover from the&nbsp; ailment.<br /><br />And it is also being suggested that he will not feature in the Super Eagles next two friendlies against Bolivia and Ghana.<br /><br />So far this season, Mikel has donned the colours of Chelsea 13 times in the English Premier League.<br /><br />Photo Credit : Twitter<br />