Relegation-threatened Newcastle said Barton, who was injured during the 2-1 defeat to Manchester City on Wednesday, had broken a fifth metatarsal.
"Joey will undergo surgery on Friday and is expected to be out for around eight weeks," the club said on their website.
The injury was identical to the one Barton suffered to his left foot at the start of last season.
The player, who was handed a six-match suspension earlier in the season for attacking a former team mate at previous club Manchester City, also damaged medial ligaments in his right knee last November.
Newcastle striker Michael Owen could also face a lengthy absence after injuring his ankle in the same match. The former England international was having a scan on Thursday.
Newcastle are 16th in the 20-team Premier League, just two points and two places clear of the drop zone.
NEWCASTLE FANS! Check FourFourTwo.com’s ever-expandinginterviews archivefor more stuff to read:
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Q&A Joey Barton
One on One Michael Owen, Kevin Keegan, Les Ferdinand, Faustino Asprilla
Boy's A Bit Special Steven Taylor, Danny Guthrie
Ask A Silly Question John Barnes
Perfect XI Ruud Gullit
What Happened Next? Tony Cunningham
My Secret Vice Nolberto Solano, Sam Allardyce
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