His former team Brentford were not scheduled to report back for training until a week after United’s players, and so the 25-year-old stayed mainly in the gym rather than get involved in his new club’s team sessions.
It explains why he is behind the rest of Ruben Amorim’s squad in fitness terms and was not involved in Saturday’s victory over West Ham at the MetLife Stadium.
Amorim has already said Mbeumo will also sit out Wednesday’s encounter with Bournemouth in Chicago.
However, the forward may be involved in the final match of the Premier League Summer Series against Everton in Atlanta on 3 August.
Mbeumo is unfazed by having to wait to make his United debut.
“My first aim is to make sure I’m ready for the start of the season, so I’ll keep working hard,” he said.
That opening-weekend encounter with Arsenal at Old Trafford is followed by a trip to Fulham.
While United do have a good record at Craven Cottage, it is the type of test that has repeatedly proved beyond them over the past few years.
And Mbeumo’s old side Brentford have proved particularly difficult opponents, winning two and drawing one of their last three meetings at the Gtech Community Stadium.
Mbeumo scored in the first of those games, setting the seal on a 4-0 victory in August 2022 that proved the trigger for United’s transfer window panic and resulted in them spending £155m to bring Casemiro and Antony to the club before that summer’s transfer window closed..
It is that profligacy United are trying to correct now, led by chief executive Omar Berrada and technical director Jason Wilcox.
Mbeumo and fellow big-name arrival Matheus Cunha at least fit into Amorim’s famed 3-5-2-1 system as the two number 10s.
He was convinced, as was Cunha, by a vision which goes beyond the current campaign, which features no European football at all, let alone the Champions League, which was on offer from his other suitors, which included Newcastle and Tottenham, now managed by his former boss at Brentford Thomas Frank.
“Of course, I spoke to some others because I wanted to hear their projects but the Manchester United one was very good for me,” he said.
“Ruben [Amorim] says ‘we are people who like winning, and we want to be the best team’, which is what we will try to do.
“I’m someone who likes a challenge. Manchester [United] are a big club. I think it’s a great opportunity and I wanted to be part of it. That’s why I chose the project.”
