Chelsea manager Antonio Conte expressed optimism about the extent of the injury that curtailed striker Alvaro Moratas involvement in Saturdays 1-0 loss at home to Manchester City.
Conte hopes Morata's early exit spared him from a more serious injury, although he said the 24-year-old was unlikely to be able to join up with the Spain squad for their World Cup qualifiers against Albania and Israel.
"It's a muscular problem. I don't think it's a serious problem," Conte told his post-match press conference.
"Because it stopped before becoming a serious injury. He said to me: 'Coach, I prefer to stop myself otherwise I risk a bad injury.'
"The doctor in the next days has to check the situation. I don't think he's available for the national team."
Morata has scored seven goals in eight games for Chelsea since signing from Real Madrid during the close season.
Kevin De Bruyne's second-half goal earned City a 1-0 win that took them back to the top of the table, above Manchester United on goal difference, and left Chelsea six points off the pace in fourth place.\