The 19-year-old arrived at the Theatre of Dreams with high expectations from Atalanta BC in January 2021, with the Red Devils forking out £19.2m to secure his signature.
However, Diallo struggled to force his way into the attacking line over Marcus Rashford, Anthony Martial and Bruno Fernandes, and his situation was not helped by Cristiano Ronaldo and Jadon Sancho's signings.
The Ivory Coast international was shipped out to Rangers on a temporary deal over the winter, but he only made 13 appearances for the Scottish giants over the course of his six-month stay, scoring three goals.
Diallo failed to complete the full 90 minutes for Rangers on any of those occasions, while he was also an unused substitute in all nine of their Europa League games en route to the final.
The arrival of Erik ten Hag has given Diallo the chance to prove himself under a new manager, but the teenager's chances of regular action at Old Trafford in 2022-23 still seem slim.
According to journalist Fredrik Filtvedt, Diallo is pushing for another loan spell elsewhere for the 2022-23 season as he aims to boost his development with consistent game time.
Filtvedt adds that Diallo and Ten Hag have spoken since the latter's appointment at Old Trafford, but as things stand there has not been a decision on the youngster's future.
Diallo has made nine appearances for Man United's senior team since his arrival in England, scoring one goal and registering one assist while making two starts in the Premier League.
The Ivorian only made one appearance for the club last term before making the switch to Ibrox, though, as he played 68 minutes against Young Boys in the Champions League.
However, Diallo has amassed an impressive six goals and four assists from five games for the Under-23s, and he has four caps under his belt for the Ivory Coast national team.
Ten Hag is expected to welcome a new attacker to Old Trafford before the new Premier League season kicks off having lost Jesse Lingard and Edinson Cavani on free transfers in recent weeks.
With Liverpool-bound Darwin Nunez seemingly off the list, the Red Devils could attempt to prise Robert Lewandowski away from Barcelona amid the Pole's vocal desire to leave.
Lewandowski remains under contract at the Allianz Arena for another 12 months, though, and director Hasan Salihamidzic has consistently ruled out the possibility of the 33-year-old leaving.
The Red Devils also remain in hot pursuit of Barcelona midfielder Frenkie de Jong but are believed to have had a first bid for the Netherlands international rejected by the Blaugrana.