Roma were not put off by Adem Ljajic’s hazelnut spread habit. Nearly three years have passed since Sinisa Mihajlovic launched his famous criticism of the player, saying that he should “cut his hair, eat less Nutella and not live his life attached to a computer”. Ljajic has trimmed his locks in the interim, but there is no word yet of him giving up on either of his preferred snack or pastime.

Walter Sabatini seems not to mind. Roma’s director of sport was handed an unenviable task this month when the club’s owners concluded that further sales were required in order to balance their books. Sabatini had little trouble lining up Tottenham as potential suitors for Erik Lamela, but needed to find a lower-priced replacement before he could allow the Argentinian to leave.

On paper, Ljajic certainly fit the bill. Like Lamela, he is a 21-year-old forward who is comfortable operating out wide or just behind the attack. Both men are expert dribblers who relish the opportunity to run at an opponent. They each had a respectable strike rate last season; Lamela scored 15 goals in 33 games for Roma, while his would-be successor hit 11 in 28 for Fiorentina.

Most importantly, Ljajic was available at the right price. With just one year left on his existing contract, Sabatini knew that Fiorentina could not afford to turn down a reasonable offer.

They had rejected an €8m bid from Milan earlier in the summer, describing it in an official club statement as “inadmissible … late, and certainly inopportune”, but their anger on that occasion had a context. Fiorentina believed Milan were trying to turn the player’s head just as he was about to sign a contract renewal. The Rossoneri had been accused of doing much the same thing to Riccardo Montolivo twelve months previously.

If anything, Milan’s bid made Fiorentina more willing to do business with Roma. It soon became clear that the Viola could not meet Ljajic’s wage demands, but by that stage they were prepared to sell to just about anyone other than Milan. They accepted Sabatini’s offer of €11m up front, plus a further €4m in potential bonuses. Ljajic signed a four-year contract with Roma, worth approximately €1.9m per year – more than three times his previous earnings.

A year ago today, the prospect of Ljajic landing such a contract would have seemed inconceivable. He was perceived back then as a pariah, an insolent and undeserving shirker who might sooner have been sent back to his former club, Partizan Belgrade, than be sought after by Fiorentina’s rivals.

His reputation had been coloured by the events of 2 May, 2012. That was the day on which he got punched by his own manager. Substituted during Fiorentina’s eventual 2-2 draw with Novara, Ljajic turned to sarcastically applaud Delio Rossi. Seconds later, the coach flung himself into the dugout, swinging fists in the player’s direction.

Words had been exchanged between the two in the seconds leading up to the assault, and though the exact context has never been revealed, many fans chose to believe the darkest of rumours. It was presumed that Ljajic must have said something truly awful to provoke such a reaction from his manager.

Mihajlovic’s two-year-old comments were dredged up as evidence that the player was a bad egg, as were complaints made by a neighbour of Ljajic’s about his late-night partying antics. Vanessa Favio claimed that the player’s get-togethers were keeping his entire apartment block awake at night. “It happens at least two times a week,” she told La Repubblica. “They go from midnight through to four in the morning.”

Further negative headlines soon followed. After the incident with Rossi, Ljajic was suspended by Fiorentina for the remainder of the season, but still got called up to play for Serbia at the end of the campaign. He was immediately sent home again, however, after failing to sing the national anthem prior to a friendly against Spain. His actions were perceived by Mihajlovic, now in charge of the national team, as an act of gross disrespect.

In reality, though, there were two sides to this story. Ljajic was raised as a Muslim and felt uncomfortable singing the anthem on religious grounds. He had apparently phoned his father before the game asking for advice. “I told him to keep his head down as much as possible so nobody saw,” said Sahmir Ljajic. “But you all know what happened.”

Many of the stories about Ljajic can likewise be viewed from another angle. We might never know exactly what was said between him and Rossi on the night of their scuffle, but we do know that portrayals of Rossi as a man who never ordinarily loses his cool are probably wide of the mark. Last season, as manager of Sampdoria, he flipped the bird at Roma’s Nicolas Burdisso in the middle of a game, earning a two-game suspension. (The defender had reportedly told him to “sit down, dickhead”.)

And while Nutella might not be the most nutritious of snacks, the truth is that Ljajic spent a significant chunk of his youth being encouraged by adults to increase his caloric intake. Dusan Trbojević, the former Partizan Belgrade youth coach (he now works for them as a scout) recalls that the player was an exceptionally skinny little boy when first spotted at age nine.

“After one game I saw [Ljajic] sitting in a car and eating an apple,” Trbojević told Serbia’s Press Online back in 2010. “As I passed, I said ‘why not get him to eat more?’ His dad immediately replied: ‘That’s what I’m talking about. He knows a thing or two with the ball, but what use is it? The opponents are larger, and they just knock him over’.”

As for the rest – the late nights and excessive video game-playing – these might be undesirable traits, but are they that unexpected for someone who was launched at age 18 into a new country with significant income and lots of free-time at his disposal? Over the last year, Ljajic is said to have reined in his partying significantly.

In the end the greatest concern for Roma fans will be whether he can live up to expectations on the pitch. Lamela has left some pretty big shoes to fill. Francesco Totti had previously gone so far as to suggest that the Argentinian could one day become his heir.

Ljajic performed at a level towards the end of last season that suggested he could be capable of reaching such heights. His form from January onwards was blistering, with 10 of the player’s 11 goals arriving after the turn of the year. By the end of the campaign he had also chipped in eight assists.

On the other hand, sceptics will point to his far less impressive showings over the previous three years. Great things had been expected of Ljajic when he signed back in January 2010. He had arrived in Florence only after a move to Manchester United collapsed – apparently because the English club could not get a work permit for the player. Sir Alex Ferguson had likened him to a young Cristiano Ronaldo.

And yet, before this season his performances had been fitful. Ljajic was in and out of the team under Cesare Prandelli, Mihajlovic, then Rossi – scoring just four goals in 50 league appearances. He drifted in and out of games, only occasionally showing off the footwork and finishing that were supposed to be the hallmark of his game.

Was his recent improvement just a purple patch, then, or the beginning of a trend? Only time will tell, though Roma do have reasons to hope it could be the latter. Ljajic displayed a notably improved attitude last season, with reporters in Florence noting that he was consistently among the first to arrive at training and among the last to leave. He worked tirelessly on his free-kicks, and went on to score from them five times over the course of the season.

So effective was, he, indeed, that some analysts have already begun asking who will take free-kicks between Ljajic, Miralem Pjanic and Totti. In reality, of course, the new arrival will need to earn a place in Rudi Garcia’s starting XI before that even becomes an issue. No one would begrudge Ljajic a little celebratory Nutella if he succeeds in that goal.