Ralf Rangnick is guilty of falling foul of something Zinedine Zidane always tried to avoid when it came to managing Cristiano Ronaldo.
The iconic Frenchman was Ronaldo's manager while the pair were together at Real Madrid and despite the Portuguese superstar's ludicrous goal-scoring exploits, he did not play every game under Zidane.
Speaking after a La Liga clash with Atletico Madrid four years ago, Zidane explained: "Cristiano is Cristiano, he has been this player all his life, scoring 50 goals a season. It is true that there is nobody else who does that.
"But others can score, have done recently, and we must think about the positives. It's better to have Cristiano with us.
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"It was just (to rest him). We have many games, that's it. Sometimes he needs to rest. These days he needs that. He feels better every day, you can see it."
Zidane's comments are in stark contrast to the reality Ronaldo currently finds himself in at Old Trafford, where the 37-year-old is more often than not required to play for the majority of every single game.
Of the 23 Premier League games Ronaldo has been available for since his triumphant return to Old Trafford, the Portugal skipper has started 20 of them.
These fixtures have come under both Rangnick and his predecessor Ole Gunnar Solskjaer.
In that same period, he has played at least more than 70 minutes in 20 of them, coming off the bench for brief cameo appearances in the other three.
That has placed an immense toll on the body of a 37-year-old forward who remains United's most potent goal threat despite the wealth of young attacking talent that surrounds him.
Nine Premier League goals this term has seemingly made Ronaldo indispensable in the eyes of Rangnick, though he has looked incredibly out of sorts in recent fixtures.
It was only a matter of weeks ago that the forward was in the midst of his worst goal drought since 2010 after going six games without a goal, though the duct was eventually broken at home to Brighton.
Since that contest, Ronaldo has put in two fairly drab performances against Leeds and Watford respectively.
The tie against the Hornets was notably poor from the former Real Madrid man who spurned a number of chances to give his side the lead.
After the game, Rangnick was asked as to whether he harboured any concerns over the amount of playing time currently required of Ronaldo and was told it appears to be having an impact.
"Yes, but we have to play with those players we have available," the German insisted.
"I spoke with him (on Friday) before the game, before the training session. He told me he was fully fit to play and that’s why I decided to have him in the starting eleven."
