, the 23-year-old said: "For the younger boys? There's a lot.
"You see Di'Shon [Bernard], Largie [Ramazani], Jimmy [Garner], you see Mason [Greenwood], obviously, coming in and Mason's on his way to being established.
"He's not quite at that level of being a regular first-teamer, and that's what Mason has to strive to become.
"He's one of the most talented players that I've seen for a long time – his left-foot, right-foot shooting is ridiculous."
Garner, 19, has already appeared for the first team, coming off the bench in a 3-1 Premier League win at Norwich.
He has featured in eight games in all competitions.
Bernard, 19, and Belgian Ramazani, also 19, have played for the side in the Europa League this season.
Despite only being 23 himself, McTominay, who has been touted as a future United captain, is happy to help bring on his younger team-mates.
He added: "For me, it's my responsibility – Marcus [Rashford], Jesse [Lingard], the more experienced ones like Juan [Mata], Nemanja [Matic], Granty [Lee Grant], for example – we've got to take a responsibility now to push these younger boys and get them up to a level where it's justifiable that they've reached their potential.
"For everyone at the football club, that's the primary goal as well. It's the same for myself: I'm getting pushed by the coaching staff every single day.
"Obviously Harry Maguire, Nemanja, Paul [Pogba], they're such influential players that you have to learn from every day.
"If the boys don't take responsibility for their own careers, it can pass you by quickly.
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"The boys who have come into the first team this year from the younger age groups have been an absolute credit."
United's players are back in training after the Premier League introduced phase one of Project Restart.
It involves social distancing training and no-contact workouts in light of the ongoing coronavirus pandemic.
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