Cardoso arrived at Betis in January 2024 from Brazilian side Internacional, and after a stellar first six months, he earned a contract extension with the club until 2030 with a reported release clause of $90.7m (€80m) - but that figure is negotiable, per the report.
Atleti would like to negotiate a lower fee with Betis over the next month, so that Cardoso could join the club this summer ahead of preseason.
The 23-year-old was named to Mauricio Pochettino's 60-man shortlist for the CONCACAF Gold Cup this week, and is in contention to represent the club at this summer's international continental tournament in the USA.