Manchester United have been credited with an interest in signing Atletico Madrid striker - and reported Chelsea, Arsenal and Liverpool target - Diego Costa, according to Sky Sports.
The Spain international is understood to have a £20million buyout clause written into his current contract, which can be activated at the end of the season.
Red Devils boss David Moyes was in attendance for Atletico's 2-0 victory over Porto in the Champions League on Wednesday night, and there have been some suggestions that he was there running the rule over Costa, who - according to Sky Sports - is 'in his thoughts'.
The 25-year-old has been in sparkling form for Diego Simeone's side this term, netting 19 goals in 20 games in all competitions for the Spanish club.
That takes Costa's overall tally to 39 goals in 64 appearances for Los Rojiblancos after returning to the Vicente Calderon from a season-long loan spell at Rayo Vallecano in 2012.
Last month, the Daily Express reported that Liverpool manager Brendan Rodgers bid for the Brazilian-born frontman during the summer, and after he snubbed the chance to move to Anfield, Chelsea and Arsenal have been monitoring his situation.
Jose Mourinho wants to bolster his ranks with a proven goalscorer in light of the ineffectiveness of his current options in attack at Stamford Bridge, while Arsene Wenger is keen to recruit a back-up for Olivier Giroud at the Emirates Stadium.