Japan midfielder Shinji Ono suffered another setback when he limped off with a calf injury in the first half of Feyenoord's 3-1 win over leader PSV Eindhoven in the Dutch first division on Sunday.
Ono, who has only recently recovered from an ankle injury, made his third straight start in the top-of-the-table clash at De Kuip Stadion but went off after 25 minutes following a crude challenge from behind by PSV captain Mark van Bommel.
"My calf hurts. I don't think it's anything too serious but we'll just have to wait and see," said Ono, who was walking on crutches after the match.
Feyenoord kept its hopes of qualifying for next season's European Champions League and the Dutch title race alive thanks to a hat trick from Pierre van Hooijdonk, who scored twice from the penalty spot and took his tally for the season to 28.
PSV is top with 80 points but its lead was cut to three as Ajax (77) thrashed Graafschap Doetinchem 7-1 at home with Feyenoord a further point behind.