Richard Dunne has left the Republic of Ireland camp to be with his wife, who went into labour on Tuesday.
The 29-year-old Manchester City player, who only joined up with the squad after Sunday's 2-2 Premier League draw with Hull, was named in the starting line-up for Wednesday's friendly clash with Poland by manager Giovanni Trapattoni.
However, he was allowed to leave Ireland's Portmarnock base to be with his wife.
He has yet to be officially ruled out of the match but Trapattoni will have to draw up a contingency plan in case he does not return.
Ipswich's Alex Bruce is also in the squad, while Paul McShane, currently on loan at Hull from Sunderland, is an option.
McShane is a central defender by trade, but has played much of his recent football at both club and international level at right-back.