LONDON (AFP) - Samuel Eto'o has yet to adjust fully to life in the Premier League with Chelsea, Blues boss Jose Mourinho said Friday.

Eto'o is still looking for his first goal for the London club following his August move from Anzhi Makhachkala.

The Cameroon striker, 32, is expected to lead Chelsea's attack at Norwich this weekend in place of Fernando Torres, set to be sidelined for three weeks with a knee ligament injury.

If Eto'o is involved from the kick-off at Carrow Road on Sunday, it will be his third league start and his fifth appearance for Chelsea in all competitions Mourinho, speaking to reporters at London club Chelsea's Cobham training ground on Friday, said the forward had lost sharpness as a result of playing in Russia.

"The player I know, the professional I know... what happened in Russia in last two-and-a-half years I didn't know," added the Portuguese who had Eto'o in his Inter Milan side that won the 2010 Champions League.

"Normally when top player is one of the top players in Europe and then goes to Anzhi the pressure goes down, the motivation and physical condition and sharpness goes down.

"Now he's back in top European football and needs a bit of time to find that sharpness. He's playing a lot. He played 80 minutes this week and he is getting his form and an understanding of where he is.

"But the Premier League is a different picture. So give him a little bit of time."

Mourinho said Eto'o had to adapt his game in order to keep playing at the highest level.

"Players transform themselves with years. They get stronger in some aspects of their game, but lose other strengths," the manager explained. "At Inter he played wide and came inside, very fast and I don't think can play the same way.

"He must be a more static player, a pure No. 9. Players have to adapt to their age, potential and condition."