Marcoussis - France captain Pascal Pape is in doubt for their second Six Nations match against Italy on Sunday after he had to leave training early on Wednesday, the coaching staff announced in a statement.
They said the 33-year-old lock -- who didn't appear to be injured when he left the session -- had not fully recovered from the 26-24 opening victory over England last Saturday which saw him win his 50th cap.
As a precaution they have retained four second row forwards in the 25-man squad, from which two players will be omitted for the match itself.
Pape's career has been bedevilled by injury, and he missed four of France's Six Nations games last year after suffering a back problem in their opening defeat by Italy in Rome.
The selectors also sent five players home to their clubs -- who have a full programme of Top 14 matches this weekend -- including wing Maxime Medard, who played the entire match against the English.
Aside from the 37-times capped Medard, the others to be sent home were back-row forward Virgile Bruni, centre Maxime Mermoz and two other wings Geoffrey Palis and Marc Andreu.
France head coach Philippe Saint-Andre will announce his starting line-up on Friday at 10:15 (SA time).
25 man squad:
Forwards: Thomas Domingo (Clermont), Yannick Forestier (Castres), Benjamin Kayser (Clermont), Dimitri Szarzewski (Racing-Metro), Nicolas Mas (Montpellier), Rabah Slimani (Stade Francais), Alexandre Flanquart (Stade Francais), Yoann Maestri (Toulouse), Pascal Pape (Stade Francais), Sebastien Vahaamahina (Perpignan), Ibrahim Diarra (Castres), Bernard Le Roux (Racing-Metro), Yannick Nyanga (Toulouse), Damien Chouly (Clermont), Louis Picamoles (Toulouse)
Backs: Jean-Marc Doussain (Toulouse), Maxime Machenaud (Racing-Metro), Jules Plisson (Stade Francais), Francois Trinh-Duc (Montpellier), Mathieu Bastareaud (Toulon), Gael Fickou (Toulouse), Wesley Fofana (Clermont), Yoann Huget (Toulouse), Hugo Bonneval (Stade Francais), Brice Dulin (Castres)