Manchester City manager Manuel Pellegrini has warned goalkeeper Joe Hart his place in the team is not guaranteed.
The Chilean is backing the England international to come good but will not wait indefinitely for him to regain top form.
Pellegrini's words come soon after a similar warning from England boss Roy Hodgson over his spot in the national side.
Hart has made several costly errors for club and country over the past year and had another uncomfortable game as City were surprisingly beaten at promoted Cardiff in the Barclays Premier League last week.
Pellegrini said: "For the moment Joe will continue being our goalkeeper but I spoke with him and he knows he must be quickly in his top form again.
"I am sure he is a top goalkeeper and will do it again.
"I said from the beginning my teams never play with names, they play with performances.
"Joe knows perfectly he needs good performances in the next games. At the moment he has all the trust."
Hart's critics have suggested that a lack of serious competition for his place in the side has been a contributory factor in his loss of form.
At City, back-up Costel Pantilimon has only been used in cup ties over the past two years but Pellegrini insists the Romanian is a serious challenger to Hart.
When asked if Hart could be dropped, Pellegrini said at a press conference: "I think it is not the moment.
"That doesn't mean we don't have another goalkeeper. We have Costel Pantilimon.
"But we know Joe has had a difficult moment and those players need trust in those moments."
Hart, 26, became City's first choice three years ago when former manager Roberto Mancini unexpectedly selected him ahead of Shay Given.
He grabbed the opportunity and was outstanding in City's title-winning 2011-12 campaign.
Pellegrini hopes the goalkeeping coach he brought with him to City will help Hart regain his best.
Pellegrini said: "I saw the whole of last season, but last season is past.
"We must see about the present and future and for this moment, I think it is best for the team that Joe Hart continues.
"Joe is working with another goalkeeping coach. I trust a lot in Xabier Mancisidor, he is a very good goalkeeping coach.
"I worked a lot with him in Malaga and Real Madrid and I am sure Joe will improve in a lot of things during the whole year.
"Joe is a very young goalkeeper, I think he arrived to the top in England maybe too young and he needs a lot of things to improve and Xabier will do it."