"Is it worth me going to the World Cup ?" Inter Milan's Eto'o told French TV channel Canal Plus Sport late on Friday.
"I still have a few days to think about it but I will see if my participation is important because I don't need this in my career."
Milla, who scored four goals as Cameroon reached the World Cup quarter-finals in 1990, said earlier this week Eto'o had done a lot for Barcelona and Inter but nothing for his national side.
Eto'o, who has scored 44 goals in 94 appearances for the Indomitable Lions, added: "What has he (Milla) done? He did not win the World Cup. They played in a quarter-final and with what a team.
"And you wonder, 'are they my people?'. Are they really my people?"
(Reporting by Julien Pretot; Editing by Alison Wildey)