Spanish side Atletico Madrid are willing to pay the release fee of Porto striker Jackson Martinez.The Colombian striker has been in superb form this season for Portuguese side Porto, scoring 23 goals in 40 appearances, adding to his 31 goals in his debut season a year earlier.And, his performances have gained interest from a number of European football’s big-money clubs with the likes of Arsenal, Manchester City, Chelsea and Real Madrid all credited with interest.However, it is now claimed by Panorama,¬†Spanish giants Atletico Madrid will activate his release clause if Spanish international Diego Costa leaves the club this summer.Costa has been linked with similar clubs to Jackson Martinez and is expected to receive heavy bids from Manchester United and Chelsea.Therefore, Atletico boss Diego Simeone is keen to make a move for the 27-year-old forward.Martinez’s release clause it reportedly set at 33m.Watch Manchester United v Manchester City Tuesday night. 24 hour Sky Sports Day pass for only 9.99. No contract.