Yakubu Aiyegbeni has failed to report back to Everton following Nigeria's exit from the Africa Cup of Nations.
According to widespread reports in the British media, the striker did not show up as planned on Wednesday.
Nigeria were eliminated from the Africa Cup of Nations last Sunday and Yakubu and fellow countryman Joseph Yobo were expected back at the club in midweek.
Yobo returned but David Moyes is understood to be frustrated with Yakubu for not providing an explanation for his absence.
The former Middlesbrough man has now reportedly been hit with an £80,000 fine.
He is set to train with Everton on Friday but Moyes may decide to leave him out of the squad for this weekend's clash with Reading.
Everton have struggled without Yakubu, failing to score in their last three games, but the likes of Andrew Johnson and Victor Anichebe could again be preferred up front.