Manchester United legend Gary Neville has admitted his concerns over the Red Devils' goalkeeping situation.
Dean Henderson has returned to the club after an impressive two-year spell on loan at Sheffield United and wants to challenge David de Gea for the No.1 spot.
Henderson is keen on becoming first-choice shot-stopper for club and country after De Gea made a string of mistakes over the course of the last campaign.
It leaves United boss Ole Gunnar Solskjaer with a headache ahead of their first game of the season at home to Crystal Palace next week.
But Neville doesn't believe not having a definite No.1 is a healthy situation.
"The idea that Dean Henderson would come into Manchester United and replace David de Gea as No.1 goalkeeper straight away… it won't happen, I can guarantee it won't happen," he told Sky Sports.
"This has got 'problem' written all over it. The one area of the pitch where you need consistency and stability is your goalkeeper.
"You need to know who your No.1 is, you cannot be flip-flopping. It just does not work; I've never seen it work at any club or at international level.
"Where there is a decision to be made about two goalkeepers you have to pick your No.1, go with him and stick with him, even if there is a mistake.
"Once you take David de Gea out of the team and put Henderson in, you may as well forget about De Gea. That's coming from my experiences at United.
"The period between Peter Schmeichel and Edwin van der Sar we had Ricardo, Fabien Barthez, Mark Bosnich, Roy Carroll, Tim Howard, Massimo Taibi, many goalkeepers over a five to six-year period and there was inconsistency that certainly didn't help."
