Manchester United have an unsustainable situation at goalkeeper, with David de Gea and Dean Henderson each commanding starting salaries, neither satisfied with being anything other than ‘number one’ and no way for the club to adequately compromise or cater to both at once.

Henderson was persuaded to return to his parent club at the end of last season following two hugely important years on loan at Sheffield United, during which he helped the Blades into the Premier League and played his way into the England squad.

But the 23-year-old homegrown star has only featured sparingly so far, largely consigned to cup competitions. He also had to make do with the bench in the Champions League, although will likely now be the regular starter for as long as United remain in the Europa League.

Part of the agreement that saw Henderson stay was a bumper new contract worth somewhere in the region of £100,000 to £120,000 per week. That salary is dwarfed by De Gea’s earnings in the region of £375,000, the highest paid goalkeeper in the world, but is comparable to a starter’s pay packet at Liverpool, Manchester City, Arsenal and Tottenham.

But aside from being a vast expense that is unusual in relation to the rest of the Premier League, United cannot hope to keep Henderson happy with his current role. He is desperate to be a starter, and there appears to be no realistic chance of the club dispensing with De Gea to allow that.

De Gea, despite his still somewhat inconsistent form, remains one of the best goalkeepers in the world, and it would be close to impossible to move him on because of his salary. It would also be a major gamble to throw Henderson in at the deep end when he is still mostly unproven.

It is important not to forget that Henderson, at this early stage of his career, has only had one season of top flight football as a starter. That was in a team where he was expected to be busy. But it is a very different skill to play for a team that typically dominates possession and still be able to maintain concentration for crucial moments, while largely being a spectator in games.

Manager Ole Gunnar Solskjaer conceded recently that Henderson is ‘not the most patient guy’ and it may be that United have no choice but to let him go ahead of next season.

The choice they and Henderson must make is where to and how it will happen to best suit everyone.

The options are a permanent sale, permanent sale with buy-back clause, or another loan.

United could get the most money for Henderson with a straight sale, perhaps worth up to £30m with the right buyer. The downside there is cutting all ties with the player, who may yet be England’s number one within the next few years.

De Gea, now 30, won’t be around forever and his future will be up for discussion again within the next couple of years – his current contract runs until 2023 but has an extension clause to 2024. If United chose that moment to let the Spaniard go, it could be the perfect time for Henderson to step in as a natural replacement if he has had time to develop as a starter at good level elsewhere.

That suggests a sale with a buy-back clause or a more straightforward long-term loan would be a better option for United. Henderson himself is thought to be keen to make it at the club he first joined at the age of 14 and staying connected could be his preferred option.

The inclusion of a buy-back clause could limit the fee United could sell Henderson for because they and not the buying club would ultimately retain control of his future. It may also limit the number of sides willing to make an offer for him on such conditions.

But the plus side is that a sale with buy-back clause gives the player a more permanent home to lay down roots before he is in contention to return, rather than the more temporary nature of a loan. The downside is that United would still have to spend money to get him back, with any buy-back clause obviously going to be higher than the initial selling fee.

Perhaps the best solution in that respect would be a longer-term loan, intended to last more than one season but without the need to spend money to re-buy the player. Again, the ultimate aim of bringing him back to Manchester may be off-putting to some suitors wanting to plan long-term. But if Henderson can get two years of regular games at a club in contention for league titles and playing in Europe, it would prepare him no end for potentially taking over from De Gea in 2023.

The other side of the coin is what club he could join.

Tottenham have been credited with interest in recent days as they begin to consider a future without long serving club captain Hugo Lloris. Chelsea have also been linked in the past, but strengthening a direct rival is not understandably something United would be keen on.

The problem is that sending Henderson to other Premier League sides operating at a slightly lower level, those in mid-table, might not be enough to prepare him to be ‘number one’ at United.

A better solution would be a move overseas. In that respect, Borussia Dortmund have been linked. The Bundesliga side have already shown themselves to be a good home for English players, having signed and developed both Jadon Sancho and Jude Bellingham.

Any other top team in Germany or France would have similar impact. Serie A and La Liga could also be options, but whatever club it is in any country is important and any suitor would need to be considered on individual merit at the time.

For more from Jamie Spencer, follow him on Twitter and Facebook!