The 24-year old moved to the German side from Chilean club Colo-Colo in the summer of 2007 and the South American club would still be entitled to 30% of any transfer fee. He has since made 117 League appearances for Leverkusen and scored 10 goals last season.
Interest is thought to be high in the Chilean international. The player was reportedly keen on a switch to Bayern Munich whilst AC Milan had a bid in the region of £9 million rejected. However, the club are keen to hold out for £15 million for the versatile midfielder.
Arsenal manager Arene Wenger is keeping an eye out for midfield reinforcements with captain Cesc Fabregas again linked with a move to Barcelona. Arsenal are willing to let the midfielder leave this summer but the Champions League winners must first increase their initial £27 million bid.
French midfielder Samir Nasri has also been linked with a move away from the Emirates. He is entering the final year of his current contract but is yet to agree an extension with the club. Rather than lose the player for nothing next summer the club could be tempted to cash in on Nasri during this transfer window.