Marco Silva’s side are struggling at the wrong end of the Premier League table with just eleven points from eleven games, one above the relegation zone.
Muniz, 24, came on in the 58th minute of their 2-0 defeat to Fulham only be forced off 17 minutes later with a hamstring injury.
Fulham have now confirmed that the Brazilian forward went under the knife and is expected to return ‘early in the new year.’
The club statement said: “The Club can provide an update on Rodrigo Muniz’s injury.
“Rodrigo underwent scans and the Club sought specialist opinion following our game at Everton last weekend. He will have surgery to his hamstring over the coming days and is expected to return to action early in the New Year.
“Everyone at Fulham wishes Rodrigo all the very best for his surgery and during his rehabilitation.”