The midfielder is a hugely important cog in Marcelo Bielsa's precisely tuned machine, and his credentials as a fan favourite are only enhanced by the fact that he is a homegrown talent.
So far this season, Leeds have lost six of the eight Premier League matches that he has missed out on, and he recently passed 200 career appearances at Elland Road.
It’s little wonder, therefore, that he is valued so highly, and former Scotland manager Alex McLeish has argued that his monetary worth to the Whites is immense too.
Speaking to Football Insider, he said: “Kalvin Phillips would command a monster fee.
“Homegrown guys tend to be much more expensive. When you’re maybe casting your eyes abroad and you’re looking, you could possibly get a wee bargain here and there.
“But when you get home-grown guys like Phillips, tying him down is of the utmost importance.
“I think there’s a few clubs that could be definitely looking at a homegrown guy.”
Phillips’ current deal at Elland Road expires in 2024, and the Whites have resisted big interest in him before, with Aston Villa launching a bid to sign the 25-year-old in 2019.
Elsewhere, Football League World are reporting that Leeds are interested in signing Barnsley midfielder Callum Styles.
The 21-year-old, is capable of operating in the centre of the park or on the left flank, and has established himself as a key figure in the Tykes’ unexpected promotion push this season, featuring 36 times in the Championship.
The youngster has been in impressive form at Oakwell this term, and was named as the EFL’s Young Player of the Month for February.
Whether or not Leeds make a move may ultimately hinge on if Barnsley are able to secure promotion to the Premier League.
The Tykes are currently fifth in the Championship table with seven games left to play.
As well as Leeds, Southampton and Norwich City are both said to be keen on a potential summer raid for Styles.
We’ve gathered the best of the rest of today's Premier League transfer speculation below:
7. United willing to offload Van de Beek
Manchester United are prepared to offer Donny van de Beek in a swap deal for Juventus ' Adrien Rabiot. (Tuttosport) (Photo by Dean Mouhtaropoulos/Getty Images) Photo: Dean Mouhtaropoulos
8. Tau wants to fight Brighton future
Percy Tau is eager to stay at Brighton and fight for his place in Graham Potter's squad. (Puma Official Twitter account) (Photo by GLYN KIRK/POOL/AFP via Getty Images) Photo: GLYN KIRK
9. Leeds could struggle to land Kamara
Leeds United may struggle to land Rangers midfielder Glen Kamara this summer because they cannot offer him European football next term, according to Noel Whelan. (Football Insider) (Photo by Ian MacNicol/Getty Images) Photo: Ian MacNicol
10. Phillips would command 'monster' fee
Alex McLeish has claimed that it would take a "monster" fee to convince Leeds United to sell Kalvin Phillips this summer. (Football Insider) (Photo by LAURENCE GRIFFITHS/POOL/AFP via Getty Images) Photo: LAURENCE GRIFFITHS