Centre-back Robert Huth, who featured in the Carling Cup defeat to Nottingham Forest on Tuesday, and team-mate Tuncay have completed moves to Stoke.
Midfielder Gary O'Neil will again be missing after he finally had his hernia operation on Tuesday, with the club hoping he will return for the game with Ipswich on September 12.
Didier Digard (groin), Brad Jones (ankle), Afonso Alves (foot), Chris Riggott (ankle), Emanuel Pogatetz (knee) and Matthew Bates (cruciate ligaments) are still absent.
Boro have won three and drawn one of their opening four Championship games and are yet to concede a goal.