Kaka has found first-team opportunities few and far between this season and has been closely linked with a move away from Madrid, but the Brazil superstar gave Mourinho a stark reminder of his talents against outclassed Colombians Millonarios.
The former AC Milan player scored a hat-trick and was named man of the match in the 8-0 victory, with the other goals coming from Jose Maria Callejon (two), Alvaro Morata (two) and Karim Benzema.
Mourinho said of Kaka: "He played well, like the whole team and we maintained a solid formation before the changes.
"The performance from Kaka and from the team was very good. It's only possible because they work well, just like those who didn't get much time on the pitch.
"Kaka and the others have done enough for me to think of them and have them in mind when it comes to making the squad list."
Madrid host Deportivo La Coruna on Sunday as they look to improve on a disappointing start to the season which has seen the champions pick up just seven points from their opening five La Liga games, eight points less than leaders Barca.