Chelsea are likely to sell one of Oscar or Eden Hazard as they anticipate offers for both midfielders in the summer, according to reports.
The Telegraph claims that manager Jose Mourinho had warned both players and German international Andre Schurrle that they must improve.
The Portuguese coach criticised Hazard last week for not being a team player and suggested that Brazilian playmaker Oscar could be saving himself for the World Cup this summer.
However, Paris Saint-Germain could test Chelsea's resolve with bids for one or both of the attacking duo at the end of the season.
Meanwhile, it is thought that the Blues will look to sign Atletico Madrid pair Diego Costa and Filipe Luis, while also recalling keeper Thibaut Courtois from his prolonged loan spell in the Spanish capital.
The Belgian's return to the club has been hastened by the injury to Petr Cech, with the Czech Republic shot-stopper set to undergo surgery and miss the start of the season.
