Chelsea's Diego Costa will have scan on Monday to assess a hamstring injury suffered in the 3-2 win at Hull.
The striker, 26, scored his 20th goal of the season but was replaced by Loic Remy with 15 minutes remaining.
The injury will cast doubt on whether Costa plays for Spain in the international break.
Premier League leaders Chelsea, who are six points clear of Manchester City with a game in hand, do not play until 4 April against Stoke.
Spain host Ukraine in a Euro 2016 qualifier on 27 March before travelling to the Netherlands for a friendly four days later.
Costa missed four matches earlier in the season with a hamstring injury combined with a viral infection.
Chelsea boss Jose Mourinho said Costa's injury his will not affect Chelsea's Premier League title challenge.
He said: "If he cannot play in the next game against Stoke in 15 days, we have Remy, we have Didier Drogba.
"We know his hamstring is not a strong one. He works hard in the week to compensate for the weakness he has there but the injury can come.
"He tried to play the Champions League final for Atletico Madrid [last season] and was injured again and again and again. He has this fragility."
Chelsea's victory over Hull came after Costa and Eden Hazard had established an early 2-0 lead, but the hosts equalised through Ahmed Elmohamady and Abel Hernandez following an error by goalkeeper Thibaut Courtois.
It threatened to extend Chelsea's uncertain recent form - they had won only two of their previous six games in all competitions.
But Mourinho said he is confident about his team's run-in, which features games against Manchester United, Arsenal and Liverpool, and refused to criticise the 22-year-old Belgium international.
"Our position is our best since the start of the season," said Mourinho.
"The maximum distance we've had is eight points with the same number of matches. Now it's six and a match in hand with nine matches to go.
"After the international break will go back to one match per week, except our game in hand. I believe we can finish the season very strong."
The Portuguese added: "Courtois is a big player. If every ball that comes to his feet he kicks into the stands then he never concedes this goal, but we don't want that.
"Maybe it was a bad back pass; maybe he was waiting for more movement from the players. But we won and that is important."