
Middlesbrough strikers Afonso Alves and Mido could face internal disciplinary action after they failed to show up for the first day of pre-season training.
Press reports claimed Tuncay had failed to return without notice but boss Gareth Southgate had authorised his absence following Turkey commitments.
Andrew Taylor and Adam Johnson were also rested after their England duties.
"Some of our players had permission to return to training at a later date and some did not," said a club spokesman.
Egyptian international Mido spent the second half of last season on loan at Wigan, while Alves scored just four league goals as Boro were relegated for the first time in 11 seasons.
bbc