He hasn't yet decided, but Best is a major doubt for the play-off game.
The 25-year-old suffered toe and groin injuries in his club's 2-1 Barclays Premier League victory over Everton and was replaced by Hatem Ben Arfa with 17 minutes remaining.
Nottingham-born Best, who was only drafted into the squad on Thursday, was expected to join up with the squad in Malahide on Monday to be assessed by Giovanni Trapattoni's medical team, but the signs are not good.
The former Coventry frontman's wife is also due to give birth imminently, and that too could delay his departure.
Alan Pardew: "Leon's wife is imminent and they are in discussions.
"He is desperate to play, don't get me wrong.
"We have spoken to the manager and spoken to the medical team about maybe a bit of compassion in terms of him staying about today because she's that close, so we will see."