Manchester United's season rests on outcasts Harry Maguire and Victor Lindelof

One of the enduring realities of football is that, just as one door appears to be closing, another has a habit of opening up and this is where Harry Maguire and Victor Lindelof now find themselves at Manchester United.

Frozen out for much of the campaign and contemplating their futures at Old Trafford, the two centre halves have suddenly been catapulted straight into the fire and their form over the coming weeks could well prove the difference between success and failure for Erik ten Hag's increasingly embattled side.

If losing key players like Marcus Rashford and Luke Shaw to injury was not enough of a setback for Ten Hag, the news that Lisandro Martinez will miss the rest of the season with a fractured metatarsal and his defensive partner Raphael Varane is sidelined for at least three weeks is a colossal blow to the club's top four ambitions and hopes of more silverware after the Carabao Cup win.

Martinez and Varane have formed the bedrock of United's resurgence under Ten Hag this season and the significance of their loss is hard to overstate. How costly it proves to be may now hinge largely on the success Maguire and Lindelof have filling a huge void.

Ten Hag has chosen his words carefully when discussing the pair, for a long time United's first-choice centre-half pairing, but there is no denying they represent a serious downgrade on the Varane-Martinez axis. Both are uncomfortable playing a high line, their lack of pace is a frequent problem, neither possess the anticipation or nous of those they are being asked to replace (witness the number of clunky bookings Maguire collects for being late to the ball) and they tend to be targeted by opponents.

They are able to carry the ball and can pick a pass but it is some of the other elements of their games that will now face the stiffest examination.

Lindelof's shortcomings have tended to fly more under the radar given the scrutiny Maguire, United's official club captain and an £85 million purchase, attracts. But there will be no hiding for either as Ten Hag looks for them to step up and buy his side crucial time, at least until Shaw is available again as a centre-half option - a role he has impressed at on several occasions this term - and Varane possibly returns.

Shaw holds some hope of being involved against Nottingham Forest on Sunday but United can ill afford to take any chances now with the left back's fitness and whether Varane is able to play any part in the final couple of weeks of the season remains to be seen.

There were certainly no guarantees being made about that on Friday night as United fans digested the latest injury news.

It remains to be seen how United, individually and collectively, handle the damage psychologically as much as anything. Characters and mettle are about to be tested. The blunt reality is goalkeeper David De Gea and United's full-backs have looked much less comfortable with Maguire and/or Lindelof in the middle and the onus on Casemiro and the returning Christian Eriksen to provide a control, poise and an outlet in midfield is greater than ever.

Moreover, opponents are likely to be encouraged. With three of Ten Hag's first choice back four currently sidelined, they will know United can be got at, while Rashford's current absence in attack has robbed them of their biggest goal threat and counter-attacking weapon. It is also a reminder of the work to do in the transfer market this summer: the wider squad is nowhere near good enough for a club with such lofty ambitions.

Maguire has started just six of United's 29 Premier League matches this season; Lindelof only five. That tells you where they stand. Maguire will also miss the FA Cup semi-final against Brighton at Wembley on Sunday week through suspension so Ten Hag will hope he has Shaw fit to partner Lindelof for that one. There could be as many as 15 more matches to play and the margin for error in almost all of them is tiny.

Ten Hag made it clear on Friday that he has no interest in excuses. You haven't played much? So what? Players at United have to be ready when the chance comes. If they have a problem with that, the manager said, they can ship out. And that is the message here: what have you got Maguire? What have you got Lindelof?

Lindelof has attracted interest from Italy. Maguire has been tentatively linked with old club Leicester among one or two others, even if the prospect of someone paying his £190,000 a week wages and coughing up a hefty transfer fee for a 30-year-old does not make an exit straight-forward or clear cut.

United have to find a way to move at least one of them on this summer but, for now, opportunity knocks. It is time to stand up and be counted. United's season could depend on it.

Ten Hag moves ahead with transfer plans, despite ownership uncertainty

Erik ten Hag was questioned on the uncertainty surrounding the club's ownership, with the sale by the Glazer family apparently having stalled, and whether it will impact United's transfer business.

While Ten Hag would not answer directly whether the ownership issues could influence his summer dealings, the Dutchman did admit that he and his recruitment staff have multiple plans in mind, with the aim of strengthening a squad that has been badly weakened by injuries and suspensions this season.

"You always need it. All clubs have to deal with having key players missing, but then other players are coming in,” said Ten Hag.

“Of course, you always want to play your best, especially when you are in the final stages but when they are not available others have to do it and I think we proved it when they are not there.

“Last week we were discussing who has to score the goals and Marcel Sabitzer scored two against Sevilla. We talk a lot about Casemiro. We proved we can play without him against Brentford and Everton.

“We can play without him and win difficult and important games. We have to deal with it and we will do. It is also the case that when players drop out others have to take over and take the responsibility.”

That will especially be the case at Forest on Sunday, where United are without first-choice central defenders Raphael Varane and Lisandro Martinez, who is out for the season with a broken bone in his foot.

And, after the disappointment of squandering a two-goal lead against Sevilla, Ten Hag is looking for players in his ranks to take on the leadership roles left by the injuries to the experienced duo.

“They go in the direction we want but Sevilla, we went back,” he said. “We are human beings and can make mistakes, but we have to avoid it. Certain players have now to step up to take the team and control the standards.”