As someone who once worked for Chelsea under José Mourinho, watching upcoming opponents and players across Europe, Steve Walsh knows just how thorough the Portuguese will be when it comes to preparing his team for the visit of Leicester City on Saturday. “They’ll know every blade of grass that we’ve covered, every set piece. He’ll know exactly what we’re about and he’ll probably second-guess our team,” Walsh says, smiling.

Walsh is Leicester’s joint assistant manager as well as the club’s head of recruitment. He turns up for this interview with a suitcase in his hand, after an overseas scouting trip. A former school teacher who played non-league football for Morecambe, Chorley and Leyland Motors, Walsh has an interesting back story that includes spending 16 years working for Chelsea, going back to the early 1990s, when Ian Porterfield was manager.

The brother of Mickey – who spent six seasons with Porto and will be remembered by older generations for scoring Match of the Day’s goal of the season for Blackpool against Sunderland in 1975 – Walsh scouted for Bury and Chester before getting his break at Chelsea.

“Gwyn Williams took me on. He was Chelsea’s assistant manager at the time. I did the opposition match analysis but also did some scouting as well,” he says. “I was still teaching but I was paid decently for part-time work. Towards the end I was getting on a plane on a Friday after school, getting back on a Sunday and then going straight back to school again on the Monday. I think at that point it was decided I would finally make the plunge.”

Although Mourinho was in charge when he accepted the chance to go full time, Walsh reported to André Villas-Boas, who was responsible for opposition scouting. He remains close to the former Chelsea and Tottenham Hotspur manager and believes that the man who is now in charge of Zenit St Petersburg was ahead of his time with some of his ideas, even if there were a few teething problems.

“André was a real techno-kid. He designed a software program using CorelDRAW and wanted me to use it,” Walsh says. “If you were doing a diagram on team shape, you had to move the players into place. It’s easy now with what is available but it wasn’t in those days. André produced little players and you had to move them. But sometimes you would move the torso and the hands would stay or the number would move! The only trouble was that all the drop-down boxes were in Portuguese. I think I had been to watch Barcelona, because we were playing them in the Champions League, and I lost a complete night’s sleep just trying to work out this program.”

Scouting assignments required great attention to detail, something that Walsh believes is a hallmark of Mourinho’s work – “He’s very methodical, doesn’t leave anything to chance” – and extended well beyond identifying formations and set-piece routines. ‘What is their preferred method of attack? If that doesn’t work, what’s the second method and the third? How many times do they give it to the left centre-back or do they always give it to the right centre-back because he’s better on the ball?’”

Walsh also looked at prospective signings from time to time and his name has been mentioned in relation to Didier Drogba and Michael Essien, as well as Gianfranco Zola and Tore Andre Flo. He is quick to stress, however, that he was a cog in a big wheel. “I was part of the process, in the same way that the scouts that work for me are now. I went to see Drogba and Essien, as well as the other two, so you hope that the information that you relayed was [valued].”

In 2006 Walsh accepted an offer to become chief scout under Sam Allardyce at Newcastle, which is where he met Nigel Pearson. When Pearson became Leicester manager in 2008, Walsh joined him and the two returned to the club in 2011, along with Craig Shakespeare, the other joint assistant, after a spell at Hull City in between.

The trio have enjoyed great success at Leicester, culminating in promotion to the Premier League as champions last season. “Nigel makes the decisions,” Walsh says, “but I would say he makes informed decisions based on a lot of knowledge from a lot of people, so it’s a real collegiate approach.”

Recruitment has been shrewd. Walsh has good contacts at Manchester United – a steady stream of players have been brought in from Old Trafford – and they have plucked a couple of gems from French football, in Anthony Knockaert and Riyad Mahrez. “People think ‘Moneybags Leicester’ but that’s wrong. Our spend record is good,” Walsh says. “We’ve bought one player [Leonardo Ulloa, £8m from Brighton] in so far this summer.”

Ulloa had been on the radar for a while. “I watched him quite a lot, the first time against [Nottingham] Forest and I came away thinking: ’He’s not bad, I need to keep an eye on him’,” Walsh says. “So we had him watched quite a few times, and then after all our players had been out celebrating [promotion] we played Brighton at home and he took advantage – he beasted us. I said to the two centre-halves, Marcin Wasilewski and Wes [Morgan]: ’Who is the hardest forward you’ve had to mark this season in the Championship?’ They both said Ulloa.”

For Walsh, who sits alongside Pearson in the stand at matches rather than on the bench, the trip to Stamford Bridge will bring back a few memories and also raise the possibility of exchanging a few words with Mourinho. “Will he seek me out? I don’t know. I hope he remembers me,” Walsh says, smiling. “I’ll make a point of trying to see him.”

The level of post-match hospitality may well depend on the result. “Chelsea played really well against Burnley but I’m looking forward to the game,” Walsh says.

“We’ll treat all our opponents with respect this season but not fear them. And we’ll try and impose the way we play, whether against Chelsea or anyone else. We’re not a team that parks the bus. We’ll try to win the game. That’s Nigel’s philosophy.”