European Cup winners are really eager to sign a Leeds United player this summer transfer window, according to a recent report. The Whites are preparing to face Southampton in the Championship playoff final at Wembley this Sunday. That said, they still don’t know what division they are going to be in next season, which is making transfer planning very tricky. Now, it has just come to light, that one of their star players is wanted by a European Cup winner. READ MORE: EFL manager predicts who’ll win when Leeds face Southampton in Championship playoff finalBayer Leverkusen want to sign Leeds Unit…