Carter is expected to stay with the squad for the second leg of the UEFA play-off in Nottingham on April 21, the last day of the Football League season when Blues will play Sheffield Utd at St. Andrew's.
"I'm reporting to England after Rotherham for the first leg in Lithuania on Wednesday," the midfielder told The B'ham Evening Mail.
"If we beat them by a few goals I might be released but that will be down to the coach and it probably wouldn't happen.
"I'm preparing myself to take part in both games and then once I'm back I'll see where we've finished in the League."
Carter is well aware that his absence could be costly, given the St Andrew's competition.
"There is a great togetherness among the lads at the moment, those not playing wish the ones who are 'all the best'.
"But if you miss out in the team it's hard to get your place back. The gaffer rested me a couple of times and I was gutted, I just want to play. But you have to accept it is a squad game nowadays, especially at a club like ours."
The news of Carters international commitment follows reports that Blues' on-loan midfielder Michael Hughes is likely to be sidelined for up to four weeks with a recurrence of the ankle injury which delayed his signing from Wimbledon last month.
Irish international Hughes has returned to Selhurst Park for treatment and news of the extent of the injury is expected soon.