Ajax captain Siem de Jong faces a spell on the sidelines after suffering a tear in his right hamstring during Sunday's draw with NAC Breda.
The Netherlands midfielder was withdrawn after eight minutes of the goalless stalemate and replaced by Kolbeinn Sigthorrsson.
De Jong is now faced with a lay-off that will ensure he misses the crunch clash with second-placed FC Twente, who are now seven points behind the Amsterdam club in the race for the Eredivisie title, a week on Sunday.
Ajax revealed that his injury will be re-examined in two weeks as he also faces up to the disappointment of missing the KNVB Cup semi-final against AZ Alkmaar..
"The midfielder was examined on Monday at the hospital," read a statement on the club's official website.
"This study found a tear in the right hamstring, which means De Jong will not be used in the coming weeks."
De Jong, who was linked with a move away from the club in the close-season, has scored seven league goals in 18 appearances this term.