The Magpies have confirmed that the one-time England international suffered the injury against his former club Manchester City on Wednesday night.
Barton limped out of the action in the second half of the 2-1 reverse at Eastlands, throwing his boot away in frustration as he trudged down the tunnel.
Joe Kinnear admitted after the match that Barton had heard a 'crack' which has now been diagnosed as a fracture to the fifth metatarsal in his right foot.
A statement on the club's official website read: "Joey will undergo surgery on Friday and is expected to be out for around eight weeks.
"The injury is identical to the one Joey suffered to his left foot at the beginning of last season."