The now 23-year-old joined the Whites from York-based i2i Football Academy in 2016, signing a professional deal in LS11 after impressing on trial.
Vieira went on to make 71 appearances for Leeds across all competitions, becoming a regular in the heart of the club's midfield during his few seasons in West Yorkshire.
He was, though, sold in 2018 to Serie A outfit Sampdoria in a bid to raise transfer funds and meet financial fair play criteria amid the arrival of new head coach Marcelo Bielsa.
Vieira earned acclaim among supporters for his no-nonsense style of play and was another of a number of exciting youngsters to emerge from Thorp Arch.
He represented England's Under-21s while on the books at Elland Road despite also being eligible to play for Portugal and Guinea Bissau.
Here, Leeds supporters share their memories of the former Whites player...
George Robinson: "Similar to Delph in that he came in to the first team and made an instant impact. I wouldn't say he was top drawer but he was good for the level we were at at the time. Would I have him back? Absolutely as he had a bit of that devilment in him that we miss when Philips doesn't play."
Nigel Howard: "Good player, he went too early which was a bit of a shame."
Stephen Long: "I'd have him back. He’s just what we need for cover for when Kalvin Phillips is absent."
Colin Vasey: "His winning goal against Norwich away caused some limbs."
Ren Rocco:" On his day he was absolutely awesome for Leeds."
David J Díaz: "His goal against Norwich always sticks out in the memoru. He was a solid player who should have never been sold, in my opinion."
Jez Serlin: "He was a great young player. We can only imagine how much a few years with Marcelo Bielsa would have improved him. Frightening."
Jon Mountford: "I thought we should never have sold him."
Paul Atkinson: "It was either him or Kalvin Philips that needed to go to fund Patrick Bamford's move if memory serves. It’s a shame he couldn’t stay."
Tommi Eccles: "He would have been a tank under Marcelo Bielsa this kid."
Gary Flockton: "Exactly the sort of player we could’ve done with now to give us more options in midfield, but three years better and more mature. Could’ve developed at the same rate as Kalvin Phillips, I think."
Stephen Eastwood: "He's one past player I'd bring back if the price is right."
Aaron Stone: "Should never have sold him. I was really annoyed when it happened."
Nathan Jones: "Goes without saying that strike at Norwich away was his best moment for us."
Gareth Harris: "I’d take him back. He was a good player on his day."
Neil Hemingway: "I met him in December 2017. He was a lovely young lad. Got a picture too. Felt like another great talent. Would take him back definitely."
Mark Rooney: "His goal v Norwich City to make it 3-2 caused absolute carnage."