Instead, the former Manchester United defender thinks his fourth official Michael Oliver played a key roll in the £50million man being given his marching orders.
Walker was sent off after picking up two bookings in the stalemate at the Etihad.
The first booking came after bringing down his opposite number Leighton Baines before he was given a second, perhaps harshly, for contact with Dominic Calvert-Lewin.
It could be argued that the youngster who set up Wayne Rooney for his 200th Premier League goal made the most of the contact.
But despite appeals from Walker – who was making his 200th Premier League appearance – and the rest of the Man City team, Madley brandished a red card.
Speaking after the fixture Gary Neville, who was adamant the referee got the decision wrong, suggested Madley might not be entirely to blame.
“I genuinely thought at the time that Michael Oliver was involved, the fourth official,” Neville explained on Sky Sports.
“We did the referee thing last year and the fourth official’s view of it, he sees it just down here, near [Pep] Guardiola and [Ronald] Koeman.
“I think the fourth official might have been involved in this, but we won’t know the referees probably won’t tell us.
“They are in communication, they’re in contact, we know that, they are an active official.
“We won’t know – obviously we don’t get to interview the referees – but I think he was given information.”