Anthony Watmough could be forced into an immediate retirement from the NRL as he continues to battle a chronic knee injury.

The 32-year-old Parramatta second-rower had surgery on his knee last July, but has struggled to train through the pre-season and is set to call it quits, according to News Corp.

The 303-game veteran is contracted to the Eels until the end of 2018, after signing with the club from Manly before the 2015 season.