Eto'o doubtful for Dynamo Kiev clash
The Cameroon international missed Saturday's 5-0 win at Genoa with a foot problem but is being given until the last moment to prove his fitness with Mario Balotelli suspended for the Group F game.
Midfielder Esteban Cambiasso is also carrying a knock.
"Today they couldn't train with the group but we'll be able to tell if they can play tomorrow. Samuel will at least be in the squad," Mourinho told reporters on Monday.
Balotelli played up front on his own at Genoa where the absence of fellow striker Diego Milito was also forgotten thanks to Inter's powerful display.
Argentina's Milito has been missing for three weeks with a hamstring injury but Mourinho said there was an outside chance he could feature on Tuesday, although midfielder Thiago Motta is out.
Dynamo are without first-choice keeper Olexandr Shovkovskiy due to a stomach problem, the club said on their website.
Taking his place will be the experienced Stanislav Bogush or Oleksandr Rybka.
Inter have two points from their opening two group games, having drawn with Barcelona and Rubin Kazan.
"It won't be a decisive game against Kiev. There are still four games and 12 points to finish the group," Mourinho added.
"The best way to prepare for Kiev was to have a moment of joy (at Genoa)."