Pantilimon has started City's last four games, after claiming the number one jersey at the Etihad Stadium from Joe Hart, and will replace Ciprian Tatarusanu.
The Steaua Bucharest goalkeeper has been withdrawn from the squad by Victor Piturca due to a back complaint, with the coach also missing Tottenham defender Vlad Chiriches due to a broken nose.
Pantilimon was not initially included in the national squad and has not featured for his national side since the 4-0 defeat to the Netherlands in March but could be called upon for his country's vital play-off.
The first leg takes place in Pireas on Friday, with the return the following Tuesday in Bucharest.
The goalkeeper failed to make a top-flight appearance for City in his first three seasons with the club but started against Norwich City and Sunderland in recent weeks, with hart dropped for a string of costly mistakes
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