His impact at Manchester United has been sensational. On paper, the Swede is half-a-decade past his peak years and yet his scoring record over the past couple of seasons has been better than ever. Some were sceptical of his tally in Ligue 1, where Paris Saint-Germain enjoyed an extraordinary level of dominance, but Ibrahimovic has brought that form to the Premier League too. After some curious misses from point-blank range during the autumn, he's been near-flawless in recent weeks and has more than justified Jose Mourinho's decision to give his trusted old striker a call.

The only problem with Ibrahimovic's extraordinary form, however, is that Manchester United have come to completely depend upon him.

This reliance has essentially been the case for Ibrahimovic's sides throughout his career: at Ajax, Inter, Milan and PSG, those teams were based almost entirely around him and Ibrahimovic was consistently fantastic. At Juventus and Barcelona, however, he was merely one of many superstars and was less impressive. If you want the benefit of Ibrahimovic's extraordinary goal-scoring ability, it seems that others must sacrifice their level of importance in the side.

This has been obvious at Manchester United this season, with none of Mourinho's other forwards enjoying particularly sparkling campaigns. Wayne Rooney, for example, has been marginalised. Primarily this has been because of his own decline rather than Ibrahimovic's impact but Rooney had grown accustomed to his sides being built around him: both United and England afforded him free roles and others would sacrifice themselves to make the system work.

That was never likely to be the case at United this season, with both Ibrahimovic and Paul Pogba rightly considered more important players; their demands naturally take precedence over Rooney's. In fairness, Rooney has happily played a supporting role before, both for Cristiano Ronaldo and Robin van Persie, but he's perhaps no longer fully capable of exerting a great influence upon matches.

Marcus Rashford is another whose opportunities have been limited thanks to Ibrahimovic's arrival, although this might not be a particularly bad thing. Rashford remains extraordinarily young and for all his tremendous impact last season, English football is littered with young talents who peaked alarmingly young because they were burnt out in their early 20s. Rashford needs to be managed intelligently; while many remain frustrated that one of English football's best young talents has often appeared from the bench this season, it's probably the ideal role for Rashford at this point. There are few signs of his confidence dropping while the chance to learn from Ibrahimovic, arguably the best No.9 of the past decade, will surely help his development too.

The major disappointment has been Anthony Martial. Although he covets a No. 9  role, there's no reason that the French international should be unable to operate effectively from his wide-left position, especially at this early stage of his career. Indeed, the balance provided by a combination of Ibrahimovic and Martial works nicely: the one thing Ibrahimovic lacks at the age of 35 is searing pace in behind the opposition, something Martial can capably provide from the left flank.

It's certainly true that United are looking for Martial's runs less now that Ibrahimovic is the central target man, while Martial's own job is probably more about creativity than he would like, tasked with feeding the Swede whenever possible. But once again, this is a perfectly reasonable role for Martial at this stage of his career. It takes an extraordinary talent to play a crucial role for United at just 21 and Martial must serve his apprenticeship under the master before becoming a star man.

Perhaps the crucial way for United to become less dependent upon Ibrahimovic for goals, however, is to make more of his hold-up play and ability to link play in deeper roles. Far from being a mere scorer, Ibrahimovic is also a tremendous creator who can drop between the lines to pull the strings, encouraging midfield runners to push forward into scoring positions. Henrikh Mkhitaryan has done this occasionally, as has Juan Mata when afforded opportunities. But United's attacking midfielders are probably still based too much around feeding Ibrahimovic rather than supporting him with dangerous late runs of their own.

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Of course, it remains to be seen whether Mourinho wants to do this and it's entirely arguable that this doesn't make United any less reliant upon Ibrahimovic anyway. If he was to become injured, for example, United wouldn't have an obvious candidate for linking play in that manner; both Rashford and Martial tend to run in behind rather than playing a hold-up role.

Nevertheless, Manchester United have usually been at their best during the Premier League era when they've been a proper team in the final third rather than dependent upon one man. Their five years of Ruud van Nistelrooy-inspired football brought the Dutchman plenty of goals but earned United relatively few trophies by their standards. The periods before and after, when things were more harmonious and more players contributed in front of goal, brought more success.

Then again, this is a new Manchester United. Mourinho isn't a manager who cares about his club's historical style and seemingly not a manager who builds for the long term, either. Mourinho is about the here and now; constructing a side around Ibrahimovic is a tried-and-tested method of success.

United might be too dependent upon the Swede at present but if you're going to depend upon anyone, you may as well be too dependent upon a man with his extraordinary track record of goals and league titles.