The 23-year-old picked up a muscular injury in the club’s pre-season win over Real Zaragoza last weekend.
And the Frogs have announced that the winger might be sidelined for Friday's LaLiga tie at the Estadio Benito Villamarín.
“The medical tests carried out on Moses Simon confirm that the attacker presents some muscular discomfort in the quadriceps of the right leg,” read a statement on club website .
“These discomforts refer to the development of the game that the player played against Real Zaragoza at the Stadium of La Romareda during the past weekend. The Nigerian player will perform individualized work in the coming days.”
Paco Lopez’s new recruit, who was presented to the press on Tuesday, also missed out on a place in Nigeria’s team to the 2018 Fifa World Cup in Russia owing to injury .
Simon will hope to return to full fitness as soon as possible in order to prove his worth after his move from Gent.