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Luke Shaw's return will provide a huge boost for Manchester United manager Jose Mourinho.

"Like a new signing" is one of football's great cliches, often used pejoratively to sneer at the suggestion a club's failings in the transfer market can be covered up by a key player's return from injury. But in this specific case, Shaw's recovery from a broken leg after nearly a year on the sidelines will give the squad something it has sorely been missing.

It will be—at least a little bit—like a new signing.

In truth, that was how the start of the 2015/16 season felt with Shaw. He looked a player transformed from the youngster who had struggled with the step up to the big stage after his 2014 transfer from Southampton to United.

As was widely discussed at the time, Shaw took a dramatically different approach to the offseason before his second United campaign than he had his first. After his first pre-season with the club, he had said, per the Sun:

I am not at the high level of fitness [Louis van Gaal] demands. I have to get fitter to get up and down the wing. I didn’t come into United thinking it would be much harder. I thought it was going to be the same as Southampton. That’s something I think I made a mistake on.

After his second, he said, per the club's website:

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As a team we all get individual programmes for the summer. On my time off, I went to Dubai with Adnan [Januzaj] and one of the coaches. It was not a thing that I was told to do, it was just something that me and Adnan chose to do, to go out there and come back in shape for when we start the pre-season training.

The impact of the work he did in the summer of 2015 was evident during the early going of Van Gaal's final season in charge. He most certainly got "up and down the wing," providing an apparently boundless energy to both United's attack and defence. His broken leg came as a huge blow to the whole team.

Indeed, a fit Shaw could have made a material difference to the outcome of the season, especially given how narrowly (goal difference) the Red Devils missed out on Champions League qualification.

But miss out they did, and a new regime has consequently arrived at United. Full-backs providing attacking width will be no less important in Mourinho's system than it was in Van Gaal's. The Portuguese manager has often built his attack around inverted wide men cutting inside to be overlapped by full-backs.

And the personnel at United pretty much guarantee that approach. Anthony Martial and Memphis Depay will compete for the wide-left attacking berth. Martial will surely be the first choice there based on the two players' respective first seasons at the club, but whichever of the two he plays behind, Shaw will have a great deal of responsibility.

Martial's instincts will rightly take him toward goal more often than they will take him out wide. And while he displayed a surprising degree of defensive aptitude under Van Gaal, having Shaw behind him would free him up from some of those chores—he should be freer to cut inside or to stay upfield to provide an out ball in transition than he was under the Dutchman.

This will be particularly important if Zlatan Ibrahimovic plays as a lone frontman. He would not be able to spearhead counter-attacks given his relative lack of speed. With Shaw allowing Martial more licence, United's whole attack should function better.

Ibrahimovic will benefit from Shaw's presence. In his five Premier League games last season, the England international averaged an accurate cross every 90 minutes.

That number was as low as 0.6 in the season before—his difficult first campaign at United—but his final season at Southampton saw him average 0.9. His uptick in 2015-16 was a reversion to the norm.

For context, one accurate cross per 90 minutes was the eighth-best average of anyone starting five or more games at left-back in the Premier League last season.

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And generally speaking, he was aiming for Wayne Rooney at centre-forward. Ibrahimovic is a different type of forward to Rooney. He has an obvious height advantage (6'4" to 5'9") and should provide a better target.

Last season, Rooney averaged 0.2 headers at goal per 90 minutes in the league to Zlatan's 0.6. That could be put down to differences in style of play, but United averaged more crosses per game than Paris Saint-Germain—21 to 19.

Of course, Ibrahimovic played centre-forward every time he played and Rooney did not, but the United captain played enough games up front that the statistic has some merit.

Attacking is only one component of a full-back's job. Shaw's defensive work was impressive enough in last season's early going that Jamie Carragher said of his injury, per Sky Sports:

You think of how well he has performed this season, he has possibly been United's best player alongside Chris Smalling in the early weeks. He was probably about to really cement that left-back position as his own and also with England ahead of the Euros, just as Ashley Cole did for a decade.

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This is all working on the presumption Mourinho will take to Shaw. That impressive month at the start of last season should ensure he does, but when asked why he had not signed Luke Shaw for Chelsea in 2014, he replied, per the Guardian:

If we pay to a 19-year-old boy what we were being asked for, to sign Luke Shaw, we are dead. We would have killed our stability with financial fair play and killed the stability in our dressing room. Because when you pay that much to a 19-year-old kid—a good player, fantastic player—but when you pay that amount of money, the next day, we would have had players knocking on our door. They would have been saying, 'How is it possible I play 200 games for this club, won this and that, yet a 19-year-old comes here and gets more money than I get?' It would’ve killed immediately our balance and we couldn’t allow that. I don’t criticise another club for paying it. They can pay what they want. I don’t have any comment about it. But for my club we can say it would be very negative for us, especially when we can say Felipe [Luis] is much less expensive. Sometimes you have to make decisions.

He will presumably see things differently now he is at United—indeed, he may well be glad he is in charge of Shaw after all—with the issues around financial fair play and team cohesion having long since been considered by someone else. What Mourinho is left with is a player capable of exercising his instructions on United's left flank.

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During last summer's pre-season tour, Van Gaal said, per The Independent: "I think that it shall be the season of Luke Shaw, that I believe."

The opening exchanges of that campaign seemed to offer evidence for this belief. Assuming Shaw returns to first-team action uninhibited by any lasting effects of the injury he suffered, it might just be Van Gaal's prediction comes true.

A year on, this could be the season of Luke Shaw.

Advanced data per WhoScored.com.