Moura impressed in the latter stages of last season, with his hat-trick against Ajax firing Spurs to the Champions League final.
He has since been rewarded with a new five-year deal in July but is believed to be frustrated at Pochettino's lack of faith in him as a regular starter.
Moura has either been named on the bench or been subbed in each of his five appearances this season.
Dier is another Spurs player United are reportedly keeping a close eye on following his dramatic fall from grace in north London.
The 25-year-old was previously one of the first names on the teamsheet but has been relegated to the bench after falling out of favour under Mauricio Pochettino and is yet to make an appearance this term.