Jadon Sancho's future at Manchester City has been plunged into fresh doubt after it emerged that the teenager failed to turn up for training on several occasions following Pep Guardiola's decision to omit him from the club's pre-season tour of the US.

Bundesliga clubs Red Bull Leipzig and Borussia Dortmund have joined Arsenal and Tottenham in the race to sign the highly rated England Under-17 winger as he appears to head closer to the exit door at the Etihad Stadium.

Sancho was expected to join fellow rising stars Phil Foden and Brahim Diaz on City's tour of Houston, Los Angeles and Nashville over the past fortnight but he was left behind after indicating that he could leave this summer.

Sancho in action for England U16s credit: Getty Images

Sancho was dismayed at being left out and the Telegraph understands that he failed to appear for training at City's CFA training ground a number of times while the senior squad were in America, with club staff struggling to reach him.

City have offered Sancho a lucrative first professional contract amid strong interest in the player both domestically and abroad but there would have to be dramatic turn-around for him to now stay at the club.

Sancho is believed to harbour some concerns about the pathway to the first team at City given the club's poor record of giving sustained opportunities to academy graduates over the nine years since the Abu Dhabi takeover but City have made it clear how highly they value him, Foden and Diaz and view the trio as future first team regulars.

Stockport born playmaker Foden and Spaniard Diaz, who is comfortable out wide or inside, both impressed on tour in the US. Foden, 17, was described as a "gift" by Guardiola and has been chased by Barcelona and Real Madrid for years while Diaz scored in wins against both Real and Spurs.

Phil Foden impressed on the recent tour to the US credit: Getty Images North America

Leipzig and Dortmund believe they both have a strong chance of luring Sancho to Germany and would only have to pay a compensation bill of around €200,000 to sign him.

By contrast, any English suitor would face a fee being set by a tribunal and that could be high given the strong case City would be able to put forward about the extensive efforts they have gone to in a bid to keep Sancho, whom they had signed from Watford for around £500,000.

Spurs asked for Sancho to be included in the deal that saw England right back Kyle Walker join City this month (July) for £50 million but City refused to let the youngster go the other way.

Arsenal have been tracking Sancho for the past 12 months although a move to North London would not be without its complications. Sancho's best friend Reiss Nelson is at Arsenal.

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City fear Sancho has had his head turned and are thought to be unhappy about some of the overtures made to the player, who has told team-mates he wants to move.

Sancho won the player of the tournament award at Under-17 European Championships in May, when England lost to Spain in the final, and is renowned for his dribbling and explosive pace as well as possessing a serious goal threat and is regarded as one of the country's most exciting prospects, although City believe his decision-making needs work.

City almost lost another of their academy poster boys at the end of last season when centre half Tosin Adarabioyo looked like he could join Everton. But he ended up signing a lucrative new contract and could now move out on loan before the close of the transfer window on Aug. 31.