Garnacho reported for pre-season training earlier than expected, with the 18-year-old back at Carrington on June 27, and it is believed that he has made a strong impression on new head coach Erik ten Hag.
The attacker was not expected back until July due to his involvement for Argentina Under-20s in the Toulon Tournament in June, with his last competitive appearance coming on June 10.
However, the South American has been present at Carrington over the last two weeks, and according to the Manchester Evening News, he is expected to be in the squad that travels to Thailand on Friday.
Garnacho made two Premier League appearances in the latter stages of the 2021-22 campaign, debuting against Chelsea at the end of April before featuring in Man United's final game of the season against Crystal Palace.
The attacker starred at Under-18 and Under-23 level last season, meanwhile, and scored two late goals to help his side win the FA Youth Cup against Nottingham Forest.
Garnacho is thought to be in line for a new contract with the 20-time English champions, with the forward, who is capable of playing off the left and the right, making a strong impression over the last 12 months.
The teenager, who has already been in a senior squad for Argentina, joined Man United's Under-18s from Atletico Madrid in October 2020.
Garnacho will allegedly travel to Thailand for the first leg of his side's pre-season tour and then make the trip alongside his teammates to Australia for games against Melbourne Victory, Palace and Aston Villa.
Meanwhile, the same report claims that Pellistri will be given the opportunity to travel with the squad on their pre-season tour in the hope of impressing Ten Hag.
The 20-year-old joined the Red Devils from Penarol in October 2020, but he is yet to make his first-team debut for the 20-time English champions, spending time out on loan with Alaves.
The Uruguay international, who made 34 appearances during his time at Alaves, has netted three times and registered one assist in eight outings for Man United Under-23s.
"He has a contract until 2026. He will make the pre-season retreat with Manchester and will take part in the tour in Asia," Pellistri's agent Agustin Alvarez recently told Grand Hotel Calciomercato.
"He [Ten Hag] will decide, if he will stay or if he will be loaned out. In the latter case we have several possibilities between England, Italy and Portugal thanks also to the performance we had with the Uruguayan national team, where the coach [Diego] Alonso who gave him the confidence that Alaves lacked."
James Garner, Hannibal Mejbri and Amad Diallo are also expected to be in the squad, but Cristiano Ronaldo will allegedly not make the trip amid the speculation surrounding his future.