Athletic Bilbao have revealed that Kepa Arrizabalaga has triggered his release clause, paving the way for the Spanish goalkeeper to join Chelsea.
The 23-year-old has emerged as a late transfer target for the Blues, who are expected to grant Thibaut Courtois permission to join Real Madrid later this week.
Chelsea were rumoured to be in advanced talks with Athletic on Tuesday, and there has now been a significant development as Kepa's buyout clause - rumoured to be in the region of £71m - has been triggered.
That technically leaves the one-cap Spain international a free agent, with Chelsea now having to pay the money to the keeper, his agent or the company that owns him.
The Blues had also been tipped to move for either Jack Butland or Jordan Pickford before Thursday evening's transfer deadline.