ER heart-throb Goran Visnjic has reportedly quit the hit hospital drama. The Croatian actor, who plays DR LUCA KOVAC, is thought to be leaving the show at the end of the current series. However, TV bosses want Visnjic to star in a further six episodes, to allow them time to write him out of the storyline, which involves his relationship with DR ABBY LOCKHART, played by Maura Tierney. Visnjic, 34, joined ER in 1999.