Speaking in his pre-match press conference this afternoon, Mourinho revealed that two offers have been received for winger Kevin De Bruyne, but no club has yet made a formal bid for the other two midfielders.
Earlier this month, the Portuguese coach admitted that both players could leave Stamford Bridge if they wished, before adding that he would prefer to keep them at the club.
However, both have played peripheral roles under Mourinho this season, and are likely to leave in the near future.
Mourinho also confirmed that he would not be prepared for either player to leave Stamford Bridge on loan.
Mata, who has won Chelsea's Player of the Year award for the last two seasons, has been linked to several clubs over recent weeks, including Paris Saint-Germain and Atletico Madrid.
Essien, meanwhile, is reportedly wanted by AC Milan – albeit on a temporary, rather than permanent, basis.