The Slovenia international has established a reputation as one of the world's best goalkeepers during his time in the Spanish capital, and Oblak has kept 16 clean sheets from 36 La Liga outings this season.
Chelsea already own the world's most expensive goalkeeper in the form of Kepa Arrizabalaga, but Frank Lampard is supposedly seeking replacements for the Spaniard after an underwhelming campaign at Stamford Bridge.
According to AS, the Blues would be willing to offer a fee of €100m (£90.7m) in order to pry Oblak away from Atletico during the summer transfer window.
The 27-year-old would become the world's most expensive shot-stopper should that deal come to fruition, but the report claims that Diego Simeone's side are determined to keep hold of Oblak and are therefore unlikely to sanction a sale.
Oblak penned a new deal with Atletico last year, and his current contract at the Wanda Metropolitano is set to run until the end of the 2022-23 season.