Atletico Madrid have sent out under-performing Portuguese midfielder Gelson Martins to struggling French side AS Monaco until the end of this season, the La Liga club said in a statement on Sunday.
Martins, 23, made only one league appearance for Diego Simeone's side since joining as a free agent from Sporting last July and has not featured for the team in any competition in 2019.
The Portugal international joins a Monaco side who are fighting against relegation from Ligue 1, currently second bottom in the standings and three points from safety after losing 2-0 to Dijon on Saturday.
The principality club sacked Thierry Henry as coach last week, replacing him with Leonardo Jardim, who led them to the 2016-17 league title and semi-finals of the Champions League but was dismissed earlier this season.
Atletico are expected to confirm a loan deal for Chelsea forward Alvaro Morata, who passed a medical in the Spanish capital earlier on Sunday.