Manchester United have a huge issue with their most important player

They say you only know what you've got when it's gone. It has been a recurring theme for Manchester United this season.

Casemiro was not a standout performer in the weekend draw with Tottenham Hotspur, but by full-time, he was sorely missed once again. United led 1-0 when he suffered a knock in the 72nd minute; they trailed just twenty minutes later. It would have been a lot worse had Matthijs De Ligt not headed in a dramatic leveller after it.

Manuel Ugarte was brushed aside in the build-up to Mathys Tel's leveller for Tottenham and played Richarlison onside when it looked like he had won it for the home team. United have conceded 20 goals in all competitions this season, just five of those have occurred when Casemiro has been on the pitch.

The Casemiro connundrum

By that logic, it is simple to suggest Casemiro should play every minute possible. The huge issue is that he has not completed a match so far this campaign. Even with the heavily reduced fixture schedule, the 33-year-old can't be relied upon to play 90 minutes. It is an unsustainable problem that could get even worse if United fulfil their ambition of a top-six finish.

Casemiro looked off the pace for much of last season but earned a reprieve in the slower pace of the Europa League. It is little surprise his renaissance has coincided with the return to one match a week, and United would have sold him in the summer had the interest been strong enough.

A key reason he remained in Manchester was due to his huge wages. Casemiro is an excellent footballer at his optimum, but he is a luxury few can afford, even more so when he can't be trusted to play an entire match. Ruben Amorim was pushed into a corner when he was quizzed on a new contract for Casemiro ahead of the trip to face Tottenham and gave a non-committal answer.

"Yeah, we don't know what is going to happen," he said. "My goal is to continue to count with Casemiro, with Harry Maguire, that he has the same problem. I don't know what is going to happen. Let's focus on this season. I'm really happy with Casemiro, he is really important. I'm really happy with Harry, but I know what you guys are asking, let's focus on this season and then we'll see the next season."

The Brazilian is arguably the most important United player right now and the only star they do not have a functional replacement for. They can win matches with Altay Bayindir in goal, can replace De Ligt with Harry Maguire, and even get a goal without the wizardry of Bryan Mbeumo. They can't defend without the cover from Casemiro.

Yet the reality is they will have to. Casemiro will be of little use if they qualify for Europe and play twice a week for much of next season, and if they fail to do so, they must use it as an opportunity to ruthlessly overhaul their midfield options anyway. Some might argue that it would still make sense to keep the veteran around on a short-term deal with reduced wages, but Amorim can't afford any passengers and must be able to rely on every player to feature twice a week if necessary.

Casemiro is the most important United player, but it is more important that they replace him.

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