Atletico Madrid signs Leo Baptistao
The Spanish club says Leo will sign a five-year contract.
The 20-year-old Leo scored seven goals in 26 games for Rayo this campaign before an injury forced him to miss the final stretch of the season.
Atletico did not release the financial details for the transfer.
Falcao left for Monaco after helping Atletico win the Copa del Rey this season and qualify for the Champions League with a third-place finish in the Spanish league.