Mourinho has been responsible for some of that, including big-money deals for the likes of Paul Pogba and Romelu Lukaku, but he is considered to be making amends for his predecessor.
Pogba's future as a Manchester United player is uncertain despite the France worldwide being handed the captain's armband for their opening Premier League game against Leicester.
The two had exchanged tense comments in the media over the summer - primarily with Mourinho urging Pogba to replicate his World Cup form in Manchester.
"I don't think we're going to move for Pogba, but he's a great player", he told Radio Sportiva.
"I don't really know too much about what's been said or talked about but he is a Man United player and I am sure he is happy there".
"If you're not happy, you can not give your best", said Pogba.
Asked about Pogba after his side's 2-1 Super Cup win against Sevilla, Bartomeu said: 'I won't speak of any names, we have respect for all clubs and there are 20 days left.
Last week, Manchester United rejected a derisory cash-plus-players offer of £45m plus Andre Gomes and Yerry Mina for the French midfielder.
Though he has suggested all is not well at United, Pogba insisted that he will continue to give his all for the club.
"I did watch it, it was a bit boring at times, but that is what you become accustomed to with Mourinho".
"I actually like the signings Jose Mourinho has made, they're more along the lines of the players I'd like to see at this football club".
While that's a denial, however, it's hardly a definitive one, and there might be time for this story to develop more before the window for sales to foreign clubs closes at the end of August.