The 30-year-old forward has bagged six goals already this season making him one of the leading scorers in La Liga.
A number of Premier League sides have been checking on him in recent weeks, and are ready to test Valladolid's resolve.
Oscar's current deal is due to expire in the summer and he has a release clause of just over £3million - which has alerted the clubs to his possible availability.
Oscar is back at Valladolid, the club he began his career with, having spent six years away enjoying spells with Real Zaragoza and Greek giants Olympiakos.







