Premier League: Everton manager Roberto Martinez won't rest Romelu Lukaku

Everton manager Roberto Martinez admits he can't afford to rest striker Romelu Lukaku when Aston Villa visit Goodison Park on Saturday.

The 21-year-old was in sparkling during last term's loan spell but having played in the summer's World Cup for Belgium, he has failed to reproduce his best form for the Toffees so far this season - finding the net just twice since his £28m permanent switch from Chelsea.

With Arouna Kone still struggling to complete his rehabilitation from a serious knee injury and summer arrival Samuel Eto'o seen as a back-up, Martinez has set out the challenge for Lukaku to dig deep.

The Spaniard said: "Romelu is still finding his best moment of form. Any player coming out of a World Cup always takes a transitional period to get their fitness back to normal.

Romelu is still finding his best moment of form. Any player coming out of a World Cup always takes a transitional period to get their fitness back to normal.

"I think Rom has done incredibly to make himself available for the games we've had.

"Only (goalkeeper) Tim Howard has played the same amount of games and his desire to help the team has stopped him being able to concentrate on being fully fit.

"Over the next few weeks we are going to try to give him that physical element he needs, but he is a young man who will be an important player for us.

"I think Rom needs to be playing and getting his match fitness and he is too important for, us so we can't afford to give him any resting period - I don't think that would help him."

On facing Paul Lambert's side, Martinez added: "It is not a moment to assess where we are in the league. It is a period where we are working to get ourselves in the best possible position before we start the final third.

"We're taking every game slowly and for us the only concentration is Aston Villa. Villa is the last team you want to play at home. They got a very good win at Stoke - we all know how difficult it is there - and then they went to Anfield and got an impressive result there."