Manchester City manager Pep Guardiola insists he needs time to overhaul his squad and turn them into Premier League title contenders.
Ahead of hosting Swansea City on Sunday, Guardiola's team are fifth in the table and a distant 13 points behind leaders Chelsea.
"It cannot be possible to change it overnight. It's impossible," he told a news conference.
"Every player costs £45-50million so it's impossible to do that. Another thing is it's not good to change seven, eight, nine players for seven, eight, nine players.
"Firstly, it's not possible and the other thing is it's not good."
But the Spaniard also warned change was coming, saying: "We realise we have a lot of players over 30.
"For example, the full-backs are 31-32, but they are so important so we cannot change absolutely everything in one season. They are the basis.
"I can understand how important Yaya is now, how important Kolarov is, the personality of Pablo in the locker room and the problems he played with against Barcelona.
"In the end, the heart and soul of the team is the old players, the people who know the club. Sooner or later, the process is going to change."
