Diego Costa broke down during Chelsea’s victory over Stoke City.
The Brazilian born Spanish international striker was introduced at half-time but lasted just 11 minutes as his fragile hamstrings forced his withdrawal, with scans to determine the full extent of his injury to take place early next week.
Mourinho would not be drawn on an exact prognosis, but suggested Costa will miss the April 18 clash with third-placed Manchester United, which is followed eight days later by a trip to second-placed Arsenal.
“It’s too early,” Mourinho said.
“He has to go home, he has to wait 48 hours. He has to do all the scans again.
“He will be out for sure a couple of weeks, but we have seven weeks until the end of the season.
“Seven weeks and eight matches. For sure, in half of it he has to be with us.”