There is a danger in reading too much into team selections. After all, we are only three games into the Premier League season. Even so, the words of Shinji Kagawa this week suggests it is the player himself concerned by his continued omission from the Manchester United starting line-up rather than mere media hype. "Please ask David Moyes why I'm not in the side," said Kagawa. "It's hard not playing regularly. Some days the frustration is worse than others; it comes in waves."

The comments indicate Kagawa is fit and ready to play, a point emphasised by the 165 minutes of action he has enjoyed in Japan's victories over Guatemala and Ghana over the past week, netting against the latter. So why has he been overlooked? Ryan Giggs, Antonio Valencia, Ashley Young, Tom Cleverley, Danny Welbeck and Wayne Rooney have all started under Moyes so far in the Premier League with Nani featuring from the bench. As a result, it is easy to forget the status Kagawa held in the game upon his arrival at Old Trafford in June of last year.

A £250,000 signing from Cerezo Osaka in 2010, Kagawa was a key figure in Borussia Dortmund's title-winning campaign in his first season at the club. In fact, Dortmund won 14 of their first 16 league games that season, only losing their 15 game unbeaten run when the attacking midfielder was injured against Eintracht Frankfurt in December. After a wobble in his absence, he returned as a champion for a run-out in the final minutes of the last game of the season.

Shinji Kagawa - Bundesliga rankings 2011/12 Discipline Number Ranking Goals 13 10th Assists 8 6th Throughball accuracy (min 10 attempts) 64% 2nd

The 2011/12 season was an even greater triumph as Kagawa scored 13 goals and provided eight assists as Dortmund stormed to a second successive title. While Mario Gotze and Robert Lewandowski were impressive, the No.10 had a legitimate claim to being the driving force behind this Dortmund side. He was named in the World Soccer team of the year alongside Xavi and Andrea Pirlo in midfield, with Lionel Messi, Cristiano Ronaldo and Robin van Persie in attack. As a result, aged 23 at the time, United's acquisition of Kagawa threatened to be just as significant as that of Van Persie.

This was the player the fans had been waiting for. A tricky advanced playmaker with exemplary touch, here was a player with the ability to make those driving runs from midfield but also thread balls through to team-mates and play in tight situations. A next level option in much the same way that Mesut Ozil's arrival at Arsenal has been heralded this summer.

But that first season was something of a disappointment. After playing the full 90 minutes of the defeat to Everton on the opening Monday of the Premier League season, earning encouraging reviews, Kagawa had to wait until January to be given the chance to complete another match - and that was in an FA Cup tie at West Ham. He finished the season with six goals and three assists.

Many of the opportunities afforded him by Sir Alex Ferguson came in wide positions rather than the No.10 role in which he had flourished in Germany. Indeed, from October onwards, nine of his 12 Premier League starts saw him cutting in from the flanks. The situation sparked a well-documented outburst from former boss Jurgen Klopp.

"Shinji Kagawa is one of the best players in the world," said Klopp in the spring. "And he now plays 20 minutes at Manchester United - on the left wing! My heart breaks. Really, I have tears in my eyes. Central midfield is Shinji's best role. He's an offensive midfielder with one of the best noses for goal I ever saw."

Although it is difficult to argue with Klopp's assessment of a player he enjoyed such success with, Ferguson did hand Kagawa his first six United starts in a central midfield role - with limited success. Perhaps the veteran boss should have given his new signing more time to adapt but with Van Persie and Rooney available the learning curve is steepened by the need for results.

PL chances created from open play - 2012/13 Player Total Mins per chance Wayne Rooney 40 50.4 Ashley Young 26 52.8 Antonio Valencia 40 55.2 Ryan Giggs 20 58.0 Nani 10 63.0 Anderson 13 63.5 Danny Welbeck 20 64.5 Javier Hernandez 14 67.4 Robin van Persie 46 67.9 Shinji Kagawa 19 69.7

Ferguson was soon on the defensive. "The difference between German and English football is that in Germany you can't foul," said the United manager when quizzed about Kagawa's progress. "You are not allowed to touch anyone in Germany, so he has come from that environment to the Premier League which is totally different. There is a physicality to our game which is different from Germany."

Klopp, meanwhile, identified a confidence issue too. "Watching him play now I feel that he still isn't the old Shinji," he added. "The stability in his play hasn't returned and I can't see the confidence that he had when he was here." The current narrative may be that Kagawa's switch from the centre had sparked this loss of momentum but it could equally be argued that the player was taken out of the heart of the game in order to help ease the transition process.

Gary Neville saw the benefit of an education on the left of midfield. "His best position is in a central role because that's where he played for Dortmund, and he will feel he can influence the game the most there," said the former Manchester United player turned Sky Sports pundit. "But at times, earlier on in the season when he was off the front, he was a little bit lost. I preferred him on the left-hand side so he could watch the game from a different position."

A hat-trick against Norwich in March appears to highlight Neville's point. Kagawa took a starting role on the left but was given the freedom to involve himself in central areas when the opportunity presented itself. His average position and touch map show Kagawa at his best - roaming in the final third and showing that instinct for goals of which Klopp has spoken. It was his first 90 minutes in the Premier League since the opening weekend. "It was a brilliant day for him," enthused Ferguson. "He is a good finisher. His second goal was composed and intelligent, his last was brilliant."

The game came between the two legs of Manchester United's Champions League knockout tie against Real Madrid. The two matches perfectly illustrate the glimpses of potential and ultimate disappointment of Kagawa's first season in England. Selected for the away leg in Madrid, Kagawa probed for the opening and looked a real threat as United traded blows with the home side in the early stages.

"I thought in the first half-hour he was terrific and he was making some great runs through them," said Ferguson. "We thought that was going to be one of our biggest assets in the game, someone to play in the second balls and he was just unlucky with a couple of heavy touches on the ball. But he kept on opening them up and if people don't see that, it's actually unfair, but he did really well for us in the first half."

Dropped

So after following up with that hat-trick against Norwich on the weekend before the return leg, Kagawa would surely be a shoo-in for a game that Ferguson needed to win to keep his hopes of equalling Bob Paisley's British record of winning the European Cup three times? Instead he was dropped from the starting line-up. An unused substitute for Ferguson's last game in Europe.

"It is one of these situations where we regard the qualities of Real Madrid with Xabi Alonso as controller of the team," explained Ferguson. "Young Shinji Kagawa found it hard to do that defensive job in the first leg. Danny Welbeck is the best in our team at that, and that is the reason I have selected him."

In many ways, it summed up Ferguson's handling of Kagawa. Praising him to the hilt, but unwilling to trust him when the key moment came. And yet, that has not stopped him talking up the Japan midfielder to his successor. "I know a little about him as a player," said Moyes in the summer. "Sir Alex spoke in glowing terms about Shinji and how good a player he is. It was his first season in the Premier League last year. He's a young player so we hope his development continues. I look forward to working with him and hopefully he has a really good season coming up."

At the time, Moyes' words were presented as positives ones and offer renewed hope of an increased role for Kagawa. However, in hindsight, the admission that he knew "a little" about the player and the description of him as "a young player" could equally be interpreted as evidence that he had no intention of building his midfield around him.

And if that proves to be the case then Moyes will most likely take the blame. Much was made of the ticking time-bomb that Ferguson left his fellow Scot in regard to Rooney's transfer request revelations. But perhaps Kagawa was the real slow-burning fuse. "Next year he will be far better, you will see a really good player then," said the man from Govan. They are words Moyes must heed or face the consequences.