Chelsea are targeting Roma midfielder Lorenzo Pellegrini and Villarreal winger Yéremy Pino as summer signings.
The Blues are concerned about the future of attacking midfielder Mason Mount.
The England star is entering the final 18 months of his deal, but has not agreed a new contract, per The Telegraph.
The source adds that if Mount does not renew, he may be sold and replaced in the summer by Chelsea.
Roma's Pellegrini and Villarreal's Pino are the most likely players to arrive at Stamford Bridge in that situation.
Mount is an academy star at Chelsea and is now a key feature of manager Graham Potter's team.