The 18-year-old is highly thought of at Leeds United.
Vieira - who turned 18 this week - has enhanced his burgeoning reputation during Leeds' pre-season campaign so far, and the young midfielder impressed again in the Whites' 4-3 win over Guisley on Friday night, in which Garry Monk's side came from three goals down.
The sensation made his Leeds debut under Steve Evans last season and signed professional terms with the Yorkshire club in the summer.
United fans will be hoping to see much more of the starlet this season, and Phillips, who scored in Friday's victory, believes that a very bright future may await his colleague.
Asked by LUTV how good Viera could be, Phillips responded: "Yeah he could be world class. He's a great player to play with, defensively and going forward. His range of passing as well is brilliant."
A more experienced Leeds XI were beaten 2-1 by Peterborough United on Saturday afternoon in what was the club's penultimate friendly of pre season.
Next Saturday, they host Italian side Atalanta and Vieira is one of the academy graduates who might feel optimistic about facing the Serie A outfit.
Then again, Monk might be wary with regards to how much attention he is attracting, and may be tempted to keep him hidden in an effort to help him develop that bit more.
At the moment, he is just potential. There's a long way to go before he fulfills it.