Keane is expected to sign for LA Galaxy today.
Eriksson has already conceded defeat in his attempt to sign Keane.
"I saw in the papers that Robbie Keane is going to play with David Beckham. If that is right, it is difficult to compete," Eriksson told the Leicester Mercury.
"We can compete with Championship clubs but, when a player decides to go to the Premier League or if it is right Keane is going to LA, it is difficult.
"If you are player and you have the chance to play in the Premier League, you understand that is what they want to do.
"Shane Long is an example because he had the chance to go to a good Premier League club. It is not about money."