Jack Grealish: from vital and colourful member of Manchester City’s treble winners to being dropped a year later for England’s tilt at Euro 2024 glory is a sobering trajectory for a footballer whose bubbly personality and talent for making mugs of defenders give him an X-factor Gareth Southgate may regret leaving behind.

The manager’s exclusion of the wide man makes Grealish the biggest casualty for form reasons as England head for Germany next week. Harry Maguire has been a mainstay of the Southgate era but the Manchester United defender misses out owing to a persistent calf injury.

Related: Euro 2024: Gareth Southgate’s England squad – in pictures

Grealish, though, can and should feel unlucky because the manager’s cull of him from the initial 33-man party can, too, be traced back to reasons of physical infirmity during a campaign with City that was ruptured by a serious dead leg then a groin problem. This limited Grealish to 10 Premier League starts and 10 substitute appearances, with three goals and one assist.

In a disappointing end to his season he featured as an unused ­substitute in City’s last three matches, including the 3-1 win over West Ham on the final day of the league campaign that sealed the historic fourth consecutive championship, and the 2-1 FA Cup final defeat by United. This pushed Pep Guardiola into a defence of Grealish after the Wembley disappointment in which his manager stated: “He’s struggled this ­season. Jack will be back at the level of last season – I’m pretty sure.”

On Monday against Bosnia and Herzegovina he seemed to be, a near half-hour cameo from the bench showing an ability to turn it on when required, in an audition for a place in Southgate’s final squad graced by the precisely flighted ball that dropped sweetly on to Trent Alexander-Arnold’s toes for England’s volleyed second in the 3-0 victory at St James’ Park.

At 28, too, Grealish is streetwise, at his peak, has four years’ experience of working under Southgate, and during the last Euros the Birmingham-born player proved he can be a game-changer when really required. After entering in the 69th-minute of England’s last-16 game against Germany with the score goalless, Grealish launched two of his familiar lissome-legged runs down the left. They came on 75 and 86 minutes and were each followed by a cross that enabled first Raheem Sterling then Harry Kane to score, as Germany were dispatched.

Covid meant the tournament was played in summer 2021 and though Grealish was an unused substitute in the penalty shootout defeat by Italy in the final in July, a month later he became English domestic football’s most expensive player when he transferred from Aston Villa to City for £100m.

Now came the evolution from the unfettered maverick who had been his boyhood team’s captain and totem to hard-edged footballer whose first term at the champions was a fight to learn the spatial demands and differing attacking and defensive rhythms of Guardiola’s City, as 22 Premier League starts were made and three goals and three assists contributed.

In the following season the Catalan’s side became immortal by claiming the title, Champions League and FA Cup, and Grealish was a key member of the XI. Here Southgate benefited too, as Guardiola completed his remodelling of Grealish, who blended menacing wing-play with discipline and adhered to the rigid positional play demanded by the master-coach while having the licence, still, to launch driving runs from his left-sided berth.

There was only one more league start, plus two more goals and four more assists, but Guardiola now trusted Grealish in the games that mattered. He started both legs of the 5-1 aggregate Champions League semi-final win over Real Madrid, the 2-1 Cup final victory over United, and the 1-0 Champions League final win over Internazionale that sealed the treble.

After the eight-inch hematoma that caused his dead leg in September, Grealish was chosen by Guardiola in the XI that beat Urawa Red Diamonds 3-0 in the Fifa Club World Cup semi-final and defeated Fluminense 4-0 in the final. But, still, his difficult season continued and it finishes, now, in the searing disappointment of Southgate’s rejection.

With his curtains-style hairdo, warm Brummie brogue and liking for a beer, as his post-treble celebrations illustrated, Grealish is a throwback to a more off-the-cuff era when football was populated by many more Jack-the-lads who made it to the very top thanks to sublime talent. Now, though, when England kick off their Euro 2024 challenge on 16 June against Serbia in Gelsenkirchen, he is forced to watch from a sofa or sun lounger.

But, after the injuries and a season of stasis, the chance to recharge properly may prove a blessing in the long term.