Mourinho expressed disappointment this time a year ago when Pereira, who had spent the 2016/17 season on loan with La Liga side Granada, chose to pursue another loan with Valencia instead of fighting for a first team place at United.
Brazil have announced their squad for their upcoming global friendlies next month, and a few big names were left out.
Thirteen players in all from Brazil's World Cup squad are in the squad head coach Tite has announced.More news: Priyanka Chopra, Nick Jonas get engaged
Artur, who was called up but not used before the 2018 FIFA World Cup in Russian Federation, is also included after a promising start to the season with FC Barcelona.
The Belgian-born 22-year-old midfielder was among a host of new, young, uncapped faces in Brazil's first post-World Cup squad, including Barcelona midfielder Arthur, also 22.
"It's time to take a look at these players", he told a news conference in Rio de Janeiro.
Manchester City goalkeeper Ederson was left out for personal reasons and replaced by Flamengo reserve Hugo, who was included as part of an experiment to give one under-20 player experience in every squad, Tite said. "They've been really good for me, I think I've totally changed as a player and a human being after these two years", he added.