"I just felt I had to change something," he said. "And I may make changes again for Wednesday's game at Spurs.
"We will have played three games in six days by the end of the Carling Cup tie and I have got a lot of midfield players.
"Steve and Robbie ran as much as anyone else and worked as hard as anyone in Poland, and I felt I should put some fresh legs in there to try to freshen us up."
There is also concern about City's goalkeeping plight with Kevin Ellegaard being thrust into the starting line-up prematurely and young Kasper Schmeichel brought into the first-team picture as a substitute.
And although his regular first-choice will be out for the Tottenham game tomorrow, Keegan added: "I don't think that David's problem is long term but it is obviously a worry.
"The next few games will tell us whether we are going to achieve the ambitions we set ourselves. By halfway we need to be within reach of the teams slightly above us at the moment."