The Spurs boss has pulled back the curtain on the dispute that prompted the player's £53 million move to Manchester City in the summer window in a new book called Brave New World by Guillem Balague. Parts of it have been serialised in the Mail on Sunday.
Pochettino spoke of a meeting ahead of the aforementioned campaign for which Walker arrived late.
"Walker came into the room late," he said. "Not good. Something clicked in my head at that moment." He went on to add that "seeing Walker turn up late to the talk was the trigger I needed to tear into them (the players)."
Later the Spurs boss speaks of how he decided to give a chance to an in-form Kieran Trippier instead of Walker. After an international break in April, Trippier played games against Watford and Burnley, while Walker was drafted in for a clash against Swansea City.
"Walker came to my office after the Watford game," it's noted. "'Gaffer, I've been at Tottenham for nine years. I've thought about it and my heart isn't here any more. Nor is my head. I've given all I have to give. I wanted to tell you before I tell my agent that I want to leave this summer.'"
Pochettino added that he felt as though Walker had shown "an alarming lack of respect for his team-mates and a slap in the face for the club" by asking for a move while the team was competing with Chelsea for top spot.
Journalist Roberto Kusabbi relayed the conversation as detailed in the book:
The switch to City did eventually go ahead, with Spurs turning to Trippier on a more regular basis. They have also drafted in Serge Aurier from Paris Saint-Germain to offer cover at right-back.
As Squawka Football noted, for City and previously for Spurs, Walker has been a tremendous attacking outlet:
Spurs supporters will be disappointed to read that Walker's mind was elsewhere late in the campaign while his team tried to chase down the Blues.
While Chelsea eventually won by a comfortable seven-point margin from their London rivals, there were times late in the term when Tottenham cranked up the pressure. Spurs won 12 of their last 13 matches in a late surge for the line, though a slow start left them too much ground to make up.
Walker's powerful bursts forward, physicality and defensive aggression were key to the team's success. They're all attributes that were refined and developed under Pochettino too.
However, after the move to City was done, journalist Marc Benamram suggested the Spurs manager didn't view the full-back as an indispensable part of his Tottenham vision:
For Walker, the decision to move to the Etihad Stadium looks as though it's a smart one. The right-back has given Pep Guardiola's team fresh impetus on the flank, while the style deployed by the manager allows the England international to raid forward frequently, where he can so often be devastating. City lead the way in the Premier League by five points too.
Spurs also appear to have moved on, though Pochettino's revelations about the player will rile some who follow Tottenham. When Walker's City face his old side at Wembley on April 14, it'll be fascinating to see what type of reaction he gets.