Pardew: Ben Arfa set for hamstring surgery
"He needs an operation on his hamstring and he could miss the rest of the year [season]," Pardew told a news conference.
"It is terrible news. Hatem gives us the X-factor and will be a big miss."
The injury-prone Ben Arfa had been out for 12 weeks before returning to play in the first leg of their Europa League tie against Anzhi Makhachkala in which he aggravated his hamstring.