Simon Kjaer, Divock Origi, Rade Krunic and Junior Messias trained separately from the core of the AC Milan group at Milanello on Wednesday, a report claims.
As has been reported by Milan News, there was a very split group in action at Milanello on Wednesday as a number of recovering players had to undergo their own personalised programs rather than be involved with the entirety of the squad.
The team are preparing for the friendly against PSV Eindhoven in the Netherlands which takes place on December 30 and the attention will then turn to the game against Salernitana in Serie A on January 4.
The four players that are undergoing their own training regimes can be added to the list of seriously injured players which is Zlatan Ibrahimovic, Alessandro Florenzi and Mike Maignan.
Stefano Pioli will be keen to have as many of these players back to full fitness before the match against Salernitana.