Barcelona midfielder Ivan Rakitic is expected to miss his side's upcoming games against Espanyol in La Liga and Juventus in the Champions League, according to Football Espana.
The 29-year-old missed Tuesday's World Cup qualifier against Turkey after picking up a hamstring injury while on international duty with Croatia.
Rakitic was forced to withdraw in the second half of Saturday's game against Kosovo, and could now be absent for a further week.
"Barcelona midfielder Ivan Rakitic will miss the Turkey match due to minor hamstring injury, sustained during the Kosovo clash, that prevents him from playing just two days later," the Croatian Football Federation wrote in a statement.
Croatia were beaten 1-0 by Turkey in Rakitic's absence, but remain top of Group I. They are, however, level on points with second-placed Iceland, while Turkey and Ukraine are just two points behind.
"We would risk too much with Rakitic playing again," coach Ante Cacic said ahead of the Turkey defeat.
The injury has been described as 'minor', although Barcelona will now be without their first-choice midfielder for two big early season games.
First a Catalan derby against neighbours Espanyol, then the first of their Champions League group games against Juventus, the two sides likely to be fighting out for top spot.
New signing Paulinho, who captained Brazil against Colombia on Tuesday, is expected to play in Rakitic's stead.