Porto has confirmed that coach Andre Villas-Boas has tendered his resignation, leaving him free to make an expected move to Chelsea.

The Portuguese champion said in a statement Tuesday that Villas-Boas informed the club he is triggering the 15 million Euros release clause to terminate his contract, which ends immediately. It gave no further details.

Portuguese media have widely reported the 33-year-old coach is poised to join Chelsea on a three-year contract.

Villas-Boas, a former assistant of Jose Mourinho at Chelsea, won the Portuguese league and Cup and the Europa League last season - his first in charge at Porto.