LONDON • Football is defined by "sliding doors". Roads not taken can be bullets dodged as easily as they can be worm-holes to life-changing opportunities which disappear forever. Once in a while, matters work out just fine both for the man who makes the train and also the one who misses it.

Diego Simeone, the Atletico Madrid manager, and Jorge Sampaoli, the Chile coach, have been linked to the Chelsea job. Five years ago this month they were both in line for another job in a moment that would come to define their careers.

Joined by a common nationality - both are from Argentina - they are different in so many ways.

Simeone, 45, was an iconic hard-tackling midfielder, who was capped 106 times by his national team. Sampaoli, 55, quit football at 20 and spent the next two decades coaching youngsters and lower-league sides before getting his first top-flight job in 2002.

Simeone's sides mirror his personality: controlled aggression, intensity, set pieces and a healthy dose of down and dirty grit. Sampaoli is a self-described disciple of Marcelo Bielsa, but in many ways he has transcended the former Marseille savant developing his brand of breathtaking attacking football.

In December 2010, both men were interviewed to become manager of Universidad de Chile.

Simeone had won two Argentinian titles but was intrigued by the potential of "La U".

Sampaoli had bounced around South America's periphery - from Peru to Ecuador - yet his brand of football was already turning heads.

Sabino Aguad, then the club president, defied expectations and chose Sampaoli, in part because he wowed officials with detailed dossiers on each player.

Simeone, somewhat bemused, joined Catania, the Serie A side, the next January. He kept them up and then moved to Atletico, where, in four years, he has won La Liga, the Europa League and a Spanish Cup, while coming within seconds of winning the Champions League.

As for Sampaoli, he guided La U to three Chilean titles and the Copa Sudamericana, South America's Europa League equivalent.

He then took over as coach of Chile, drawing rave reviews at the 2014 World Cup and winning the Copa America last summer.

He joins Pep Guardiola and Luis Enrique on the three-man shortlist for Fifa's 2015 Coach of the Year award.

Sliding doors. Had Simeone been given the job back in December 2010, he might never have made it to Atletico. Had Sampaoli been denied it, he might never have made it on to the heavyweights' coaching radar.

We'll never know, but the chances are that neither would be talked about as possible Chelsea managers today.

Of the two, then as now, Sampaoli seems the more intriguing choice and the more accessible. Chile's tax authorities are investigating him and the Chilean FA over bonuses which were paid via third-party companies to Sampaoli and his assistants for winning the Copa.

He has maintained that he merely followed instructions and denies any wrongdoing but there is a sense that, after three years of international football, he's ready to move on.

The idea of Sampaoli working at a leading European power sets pulses racing among anyone who has seen his teams play.

He switches effortlessly between systems, all the while maintaining a seemingly perfectly choreographed synchronicity of movement, on the ball and off it, when it turns into an asphyxiating high press.

It is a balance that he achieves through hours of repetition on the training pitch, followed by more hours of film study.

His detractors said his methods, while suitable to a team of hungry no-names like the one he had at La U, could not work with established stars like Alexis Sanchez and Arturo Vidal, but he proved them wrong with Chile.

Indeed, the national team experience showed that he had evolved. Some aspects of his idealism were tempered, others were cemented, like his belief that, with the right players, you could play a centre-back pairing who stood at 1.70m and 1.77m respectively, as he did with Gary Medel and Gonzalo Jara.

Five years ago, La U chose the unknown oddball - one of his first moves was to turn down the luxury villa in a gated community that came as a perk of his contract for a one-bedroom flat opposite the training ground - over the silverware-toting up-and-coming household name.

You wonder if anyone will have the courage to make such a choice in today's even more pressurised environment.

And, if they do, whether it will have the same momentous impact as that sliding doors moment in 2010.

THE TIMES, LONDON