Costa may now be forced to pull out of the Vicente del Bosque’s Spain squad for their forthcoming Euro 2016 qualifier at home to Ukraine and friendly in Holland.
The 26-year-old has been plagued by hamstring and pelvic injuries since joining from Atletico Madrid for ??32million in the summer, but that has not stopped him scoring an impressive 20 goals in all competitions this season.
Costa bagged an early goal in the Blues’ 3-2 success at Hull City on Sunday to help maintain the west Londoners’ six-point lead at the top of the table.
However, the Brazil-born forward left the field at the KC Stadium in discomfort, giving way for Loic Remy, which proved a precipitous change as the Frenchman turned match-winner instantly.
“He has a muscular problem, there’s no doubt about it” Mourinho told Sky Sports. “When the team needs goals and the striker comes off with 15 minutes to go it’s because he feels it.
“He has already experience with the hamstrings and was clear that he had an injury but if he cannot play the next game in 15 days against Stoke, we have Remy and we have (Didier) Drogba – let’s go.”