Eto'o has not played since being substituted with a hamstring injury in the 6-0 victory over Arsenal, and remains a major doubt for the UEFA Champions League showdown at Stamford Bridge.
However, Mourinho is keen to have some added firepower at his disposal as the Blues look to overturn a 3-1 deficit from the first leg, and received a boost on the eve of Tuesday's game as Eto'o came through a training session.
Mourinho had previously indicated over the weekend that he would be prepared to take a calculated gamble on Eto'o.
'Will Eto'o be fit? Let's see. Let's see if he trains on Monday. Maybe he could play but to risk a player you need to have minimum conditions to take that risk," explained Mourinho.
"If you think he's going to be out after 10 minutes of the game you can't take that risk. If there is a minimum of risk, then yes.
"We need to score goals. If we don't score a minimum of two goals we are out. We know that, so if we can have everybody available who can give us a chance to score goals then let's do that."
Mourinho also has problems in midfield, with Ramires suspended and Nemanja Matic ineligible, but he believes Chelsea can complete an 'almost impossible' mission.
'Am I nervous about the match? No,' said Mourinho. 'I'd have been nervous if we'd won 1-0 or 2-0 in Paris, but losing 3-1 means I am not nervous. I want to enjoy the game, I want to enjoy the fight, I want to enjoy the risk. So, no nerves.
"A big game, an almost impossible job - so let's go.
"What's important is that they give everything, that they leave nothing on the field. PSG as a club don't have the experience we do."