We probably should have seen it coming. When Damien Duff was on Premier Sports for the second leg of the Champions League semi-final between Arsenal and Atlético Madrid last month, he all but told us that there was something in the pipeline with Brentford. His smile as gnomic as ever, he was so effusive in his praise of a recent trip to the club that he may as well have held up a red and white striped jersey and smiled for the camera.“Sometimes it’s the stuff that you can’t see but you can just feel,” he said. “Listen, they’re obviously in a great place in the league at the moment. The sun is out, May in London is brilliant, a nice place. Brilliant players, underrated players. Seeing them up close and personal, a high, high quality. [ Damien Duff joins Brentford coaching staffOpens in new window ]“And like I said, the feel, the feel. Just a well-run football club. It’s not always a given. You look at maybe a couple of my ex-clubs, Blackburn and Chelsea. They’re two basket cases. And that’s why they are where they are. Brentford, brilliant, like I said, from top to bottom.”On plenty of levels, it makes obvious sense. Duff has street cred as soon as he walks in the door. He was a 30-games-a-season Premier League player when most of the Brentford squad were between the ages of five and 15, their peak years of dreaming about being a professional footballer. He has currency.Also, and this is not unimportant, Duff has won a domestic league as a manager. The League of Ireland won’t count for much in a Premier League dressingroom but it does at least show the seriousness of Duff’s intentions. This isn’t Keith Andrews sorting out a gig for an old teammate.Still, it’s at least a mini-surprise. Duff has put on the record time and again the fact that a job in English football didn’t really interest him. His son is 15 and his daughter 13. As recently as 14 months ago, Duff did a press conference in Tolka Park. There was talk at the time that Bolton Wanderers had recently made enquiries as to how attached Duff was to life in Dublin. Very attached, was his answer.Damien Duff watches a Premier Division match between Bohemians and his Shelbourne team from behind the goal at Dalymount Park last year. Photograph: Ryan Byrne/Inpho “That’s my son at the back of the room. I’m here because they are here and I want to be here. [I was at] Celtic a year, or over a year, without them. I will never do that again. Football is my life and I referenced the Bill Shankly quote the other night – football is more important than life or death. But when you strip it all back, no, I’m staying with my kids and it’s that simple. I don’t look or picture myself anywhere else but Ireland.”Times change, situations change, minds change. Duff shares with that other Irish sporting chatterbox Rory McIlroy a merry refusal to be bound by statements he may have made in the past. That’s what he thought then. It evidently isn’t what he thinks now. It’s no big shock that a year kicking his heels around the house would do that to as busy a mind as his.The big question, though, is just where that kind of mind fits in with the ultra-analytical, data-led universe we are repeatedly told a club like Brentford inhabits. Duff clearly has many technical qualities as a coach. But it’s also unavoidably true that, not to put too fine a point on it, some of his success was down to the fact that he’s a bit of a mad bastard.Players were all-in because he was all-in. The force of his personality drove the Shels dressingroom. There was no length he wasn’t prepared to go to, no envelope he wouldn’t push. If that meant ruffling feathers and getting into messy scrapes with opposing managers, fans, the media, the league itself, so be it.Where does all that fit into the algorithm? What do the xG models say about it? Brentford are all about the system and the framework, about finding inefficiencies in the way things are done and exploiting them. Duff’s occasional wild tendencies look like a glitch in the matrix compared to all that.Or maybe we’re looking at it the wrong way entirely. Maybe this is exactly why they’re interested. Could this be the next frontier in analytics? Could it be that football clubs have been undervaluing mad bastards all along? It will be fun to find out.