Eto'o is in a race against time to be fit for Tuesday's crucial clash following complications with a hamstring injury.
The hamstring strain was due to keep Eto'o on the sidelines for a maximum of two weeks but the injury has taken longer to heal than expected.
Blues boss Jose Mourinho said: "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.
"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."
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