Premier League rules state that each member clubs' 25-man squad must consist of no more than 17 foreign players, but Chelsea have one extra.
It had been thought that Torres, who has struggled to find form at Stamford Bridge since his big-money move from Liverpool in 2011, would be the man to make way - particularly after the arrivals of fellow forwards Diego Costa and Didier Drogba.
But Mourinho insisted that is not the case.
"Three strikers is fundamental in the squad and we have three," he told Sky Sports News.
"'Nando [Torres] is one of them. We have a good squad.
"The perfect squad would be with this 18 players, not 17, but rules are rules and we are working hard, even here, to not have these kind of problems in the future.
"[We want] to have more English players in our squad which we are going to have in the future but in this moment we are still in the middle of this process.
"So at the moment we have to make a decision about one player not to be on that list."
Frank Lampard and Ashley Cole are two English players to have left Chelsea in the close-season, while Gary Cahill was the last high-profile home-grown player they signed back in 2012.
