man ... i heard this question a lot
those teams is about the currently season you have played in the ML ... i mean those teams changing every season to keep up with the ML rate
Example : if you played this season aginst World All Stars Team you will find (( gerrard , Ronaldo , Ronaldinho , Ferdinand , .... ))
next season if ronaldinho take a hard injury and diddnt play for a 10 match you will not find him in the team but maybe you will find schoolse because he played so will this season
because those teams is depinding on the ML rate ... and they didnt have an exactly players