When asked about substituting Rasmus Hojlund and Kobbie Mainoo against Burnley, Erik Ten Hag said:

“And then the last thing is that we have had three games [in seven days] where Burnley had days off. In a high-intensity game, it’s totally logical to bring players off who are very young and who are in their first years of the Premier League.”

“And then we don’t even talk about the injury risk. Rasmus Hojlund had more injuries already in the course of this season, Kobbie Mainoo also, he had two bad injuries.”

“So I don’t want them to get injured, so I protected them as well. So there are more reasons to make the subs.”

“But then I understand that fans want to see [those players]. They see also the skills those players bring and contribute to the team, I understand that. But I have to do my job and that is the right decision.”

In light of these comments about “protecting” younger players, let’s compare Mainoo this year to what happened to 18-year-old Pedri when he was not protected by his club and country.

At 18 years old, Kobbie Mainoo has already played 27 senior matches for Manchester United that have added up to 1,976 minutes. This statistic becomes wilder when considering that all but 152 of those have come since the 0-0 draw against Liverpool in mid-September. On top of Mainoo’s minutes for Manchester United, he has played an extra 89 minutes for England and is likely to make Gareth Southgate’s squad for the upcoming European Championships.

In the 2020-2021 season, an 18-year-old Pedri played an incredible 73 games for club and country in one season. In those 73 matches, Pedri played 3,526 minutes for Barcelona and 842 minutes for Spain.

To make this comparison more relevant, I looked at the minutes Pedri played from mid-December to this point in the season (end of April). From mid-December to the end of April, Pedri played 2,510 total minutes for Barcelona and Spain. In the same amount of time this year, Kobbie Mainoo has played 1,913. Yes, there is still a decent difference between the minutes played, but that is partly because of Ten Hag bringing Mainoo off earlier in matches, which is what is in question here.

So why are we comparing these heavy minutes by 18-year-olds? At face value, this shows how incredible each player was and is at this age and how important they were and are to their teams. However, when we look at what has happened to Pedri since that season, we see why Ten Hag is being cautious about Mainoo.

Since the 2020-2021 season, when Pedri played 73 total games, he has missed 75 games for Barcelona and Spain due to thigh and hamstring injuries. According to an article from the American Academy of Orthopedic Surgeons, muscle fatigue is a major risk factor in hamstring and thigh injuries, and “Fatigue reduces the energy-absorbing capabilities of muscle, making them more susceptible to injury”.

Pedri’s first muscle injury occurred in September of the 2021-2022 season. The Spanish center midfielder played 12 games in the summer of that year and had no summer break. The first hamstring injury forced Pedri to miss just three games, but he immediately reaggravated it and was out the next 103 days, missing 23 games for club and country.

In every season since those first injuries, Pedri has missed at least 100 days of action. This has caused him, the fans, and his teams frustration, as well as inconsistencies when he is available. The now 21-year-old has not been able to return to the incredible form he was in as a teenager and now, even when healthy, is struggling to break into Xavi’s starting XI.

So, how does all of this relate to Kobbie Mainoo? Young players are not used to playing 50-plus matches in a season. From the 2020-2021 season to the 2022-2023 season, Mainoo played a total of 62 competitive matches for the United youth teams. That is a far cry from the expectations of a first team player in multiple competitions.

So, when Ten Hag says he is protecting Kobbie Mainoo, this is what he means. Ten Hag does not want Mainoo to get overly fatigued in a way that can open the door to future recurring injuries, like what has happened to Pedri. While this can be incredibly frustrating because of Mainoo’s incredible talent and maturity, imagine how important a healthy Mainoo will be when he has a quality team around him competing for trophies and titles.

I love watching Mainoo play and am just as frustrated when he comes off early. But we have to understand the danger related to the overuse of younger first-team players, especially in a high work-rate position in the midfield.