Chelsea would have to spend €120m to begin talks with Atletico Madrid goalkeeper Jan Oblak.
Atleti boss Diego Simeone is reluctant to lose the 27-year-old, who has starred for his side since 2015.
But a cordial relationship between the two clubs - built through the transfers of Diego Costs, Alvaro Morata and Thibaut Courtois - has put Oblak's transfer on the table.
Blues boss Frank Lampard wants to replace Kepa Arrizabalaga in goals, but must first sell the Spaniard to make room for Oblak.
Valencia are interested in Kepa and would be willing to sign him on-loan for two years.
However, the 25-year-old's wages of £170,000-a-week is proving a stumbling block for potential suitors.
