Martin O'Neill says Declan Rice was not included in the Republic of Ireland squad in order to have extra time to consider his international future.
Sources have told Sky Sports News that Rice favours switching allegiance to England, despite having played three friendlies for the Republic of Ireland.
However, a source close to the 19-year-old says the West Ham defender remains undecided on his international future.
The London-born defender made his debut for the Republic of Ireland in March but was not selected for September's Nations League match with Wales and is also not part of the squad to face Ryan Giggs' team again this month after facing Denmark.
Speaking on Thursday, Republic of Ireland boss O'Neill said: "I've spoken to Declan and his family, they want a little more time to make their minds up.
"I'm comfortable with that. He hasn't chosen anyone yet."
Rice's club manager, Manuel Pellegrini, said on Thursday that he should not be pressurised into making such a "difficult decision".
Rice has held meetings with Gareth Southgate, who is a keen admirer of Rice, but it is understood the England manager will not include him in a squad until his eligibility has been formalised, which could take several weeks or months.
Asked if Rice had sought his advice, Pellegrini added: "I am always talking with all the players, Declan also.
"He is a young player and we need to give him time to make a difficult decision. We must not pressure him about which country he will play for. He needs time.
"He can be a top player. He is learning a lot and always listening and asking what he can improve. He is very young but has a huge future."
Cardiff midfielder Harry Arter has been recalled, having been previously left out following a row with assistant manager Roy Keane.
O'Neill also welcomes back James McClean, Shane Long and Sean Maguire after they missed the September games through injury, while there is also a first call-up for Richie Towell, who is currently on loan at Rotherham from Brighton.