Mourinho has three strikers at his disposal this season following the recent arrival of Diego Costa and the return of Didier Drogba but the Chelsea boss insists each of the trio are essential to his squad.
Torres has struggled to find the form which tempted Chelsea to part with £50m for his services in 2011 but in an exclusive interview with Sky Sports News the Portuguese said: "We have a good squad.
"The perfect squad would be with this 18 players, not 17 or 16, but rules are rules and we are working hard, even here, for not to 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.”
And when asked whether this one player was Torres, the 51-year-old was quick to confirm the Spain international would be staying at Stamford Bridge:
"No. Three strikers is fundamental in a squad and we have three strikers; Fernando, Didier and Diego so one of them is not going for sure," he added.
Looking ahead to next season, Mourinho has ruled out naming a vice captain claiming any member of his side is capable of deputising for long-time skipper John Terry.
"The captain is John and everyone knows that," he said. "He has been the captain for 10 years so after him anyone can be the captain. It is something I am not worried about.
"What we need to have is people with experience with personality with desire to win with the group, with club connections and a great feeling towards the younger players.
"We have so many of them that we don't need this vice-captain status."
On Thibaut Courtois' return to the squad and the battle for the No 1 spot with Petr Cech, Mourinho added: "We have competition for places all over the pitch.
"This is a club that wants to be strong and have real possibilities to compete for trophies so we need competition in every place.
"I know Mark Schwarzer is a very good goalkeeper, very stable, a group man, completely ready to be our second goalkeeper like he was last season when we needed him to play.
"So if he is our second goalkeeper we feel very safe with him, but to have Petr and Thibaut together in the same squad is a good problem for me."