David De Gea has been given 12 months to save his Manchester United career. For some, that may seem a generous period of time for a goalkeeper whose form has been in decline for the past two years, but sources have told ESPN that the summer of 2021 will be when the club addresses the thorny issue of whether to stick with the Spaniard or back the potential of Dean Henderson.

At 29, De Gea has time on his side to emerge from a slump in form that dates back to the 2018 World Cup with Spain and regain his status as the world's best keeper. United manager Ole Gunnar Solskjaer is prepared to give him the opportunity to do just that, but United also believe that Henderson, who is approaching the end of his second season on loan at Sheffield United, can become the club's first-choice goalkeeper for 10 years. The only problem is that nobody at Old Trafford knows quite when that 10 years will start, or if it ever will.

"David is not having the best of times," a source told ESPN. "But he's still capable of winning games with his ability and experience, and people at the club know that. While Dean is rated very highly, he's still only 23 and has less than a full season in the Premier League to his name. United can't risk abandoning De Gea for a kid with loads of potential but not a lot of experience. The next year will be crucial for both of them."

Speaking at his news conference on Tuesday ahead United's home game against Sheffield United -- Henderson is ineligible for the Blades due to rules prohibiting players playing against their parent club -- Solskjaer hinted at the view within Old Trafford that Henderson is improving fast, but not yet ready to displace De Gea.

"It's a different job to be playing for Sheffield United and for Manchester United," Solskjaer said. "The two years he [Henderson] has had [at Sheffield United] have been fantastic development. He's learning all the time, he's a passionate keeper, developing with good coaching. One day he'll be England No. 1 and United No. 1 and he needs to keep developing."

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In many ways, the disruption of the past three months due to the coronavirus pandemic has inadvertently bought United some time in their attempts to make a long-term decision over De Gea and Henderson.

Prior to the football shutdown in mid-March, Henderson was being lined up by England manager Gareth Southgate to make his senior international debut against either Italy or Denmark in the March friendlies at Wembley. Sources have told ESPN that Southgate wanted to test Henderson amid concerns over the form of Everton's Jordan Pickford. Had Henderson made his debut and impressed the manager, a place in England's Euro 2020 squad would have been virtually assured and, with it, the youngster's thirst for first-team action would have surely increased.

"If he had come back from the Euros as England's No. 1, it would have given United a problem because nobody can realistically see De Gea or Henderson putting up with being second choice at Old Trafford," the source told ESPN. "But that problem has now been delayed by 12 months and it gives everybody a chance to do what they need to do.

What happens next pretty much depends on De Gea. If he can put his mistakes behind him and rediscover his best form, he will be in the driving seat when United make their decision next summer, because he will still be the guy who has a Premier League winners' medal and Champions League experience on his CV, as opposed to an emerging keeper on the rise. But Henderson is a man in a hurry. After spending time on loan at Stockport, Grimsby and Shrewsbury prior to his spell at Bramall Lane, he is aware of interest from major clubs including Chelsea, Bayern Munich, Juventus and Paris Saint-Germain.

Sources at United talk of a youngster with supreme self-confidence, largely in a positive sense. If a player is to succeed at United, they have to believe in their own ability, but there is also a view that Henderson's self-belief can go too far.

One source has told ESPN that Henderson surprised former manager Louis van Gaal with his bravado after being selected on the substitutes' bench as an 18-year-old for the FA Cup tie at Shrewsbury in February 2016. When Van Gaal was congratulating his players after their victory, the Dutchman made a remark to Henderson about enjoying his first experience with the first team, only for the teenager to respond by telling the manager that he would have the keeper's shirt again for the following game at the weekend. Van Gaal took it in good humour, but was surprised by Henderson's boldness.

That same streak in Henderson prompted Sheffield United manager Chris Wilder to be surprisingly critical of the keeper following a mistake against Liverpool earlier this season, which led to a 1-0 defeat. Wilder publicly said Henderson had "do better and concentrate more," in an effort to keep him grounded.

From United's perspective, how Henderson copes with mistakes and bounces back is a crucial aspect of his development and they want him to make more, simply to gauge his ability to cope with the pressures of playing at Old Trafford. Richard Hartis, United's senior goalkeeper coach, is a big admirer of Henderson's and was a key figure in him signing a contract extension last summer. That deal expires next summer, but United have the safety net of a 12-month option within the contract.

De Gea, meanwhile, is contracted to United until June 2023 (the club also has a 12-month option in that deal), so Solskjaer has to persevere with him for at least another year.

There is no obvious buyer in the market right now, and Solskjaer is reluctant to risk Henderson's inexperience ahead of De Gea. But equally, Solskjaer and United know that there would be no value in Henderson returning this summer to spend a season on the bench as No. 2, when he could play every week on loan at another club.

Make no mistake, though: United cannot dodge the issue next summer. It will be make or break for De Gea and Henderson.