Everton manager Roberto Martinez admits he made a mistake in bringing back Ross Barkley too early from injury last month and he is now keen to ensure the midfielder is fully fit for the remainder of the season.
The 20-year-old missed three weeks in January with a broken toe but came back for the Merseyside derby defeat at Anfield, mainly as a result of other injury pressures on the squad.
Barkley was hauled off at half-time four days later against Aston Villa, before being used for only 26 minutes at Tottenham last weekend and was named on the bench for Wednesday's postponed game against Crystal Palace.
"I think Ross is so eager to play and make himself available that I did bring him back too early, especially against Aston Villa," said Martinez.
"When you come back you get through with adrenaline but you need to rest from that first game - he needed more time.
"It was too early for him to start the game (against Villa) but Ross is a young man who can get through anything.
"You have to be careful because he will never be conscious he is feeling any pain.
"He is such a joy to work with we have to make sure he has fully recovered and is fully refreshed and ready to have a massive impact from now until the end of the season.
"I am really pleased with the way he is putting himself up for the games and he wants to be ready but he is going to be vital for the final third (of the season) and we need to make sure we use him wisely and always at 100 per cent."
Barkley is expected to be included in England's squad for the friendly against Denmark in just under three weeks' time and his Everton team-mate Leighton Baines is likely to start ahead of Chelsea rival Ashley Cole.
Martinez did not want to get drawn into making England manager Roy Hodgson's selection for the World Cup but he feels Baines is ideally placed to become first choice.
"Only the national team manager knows that," he added.
"What is important is Leighton has been enjoying a very consistent season so far and the options for this England side are phenomenal.
"The pleasing aspect for English football is the amount of new good youngsters and good players that are now performing important roles at club level.
"From our point of view we have seen Leighton enjoying a very good season, a season which will get stronger in the final third with the stability of this new contract, and for us he is an important player but I know he can do that for the national team."
