Manchester United are reeling from the news that their most highly regarded youth-team player, Ravel Morrison, is facing the possibility of a prison sentence that threatens to wreck his career.

Morrison, tipped to be one of the pre-eminent English footballers of his generation, appeared at Salford magistrates' court on Wednesday charged with assaulting his girlfriend and causing criminal damage. The 18-year-old is already the subject of a 12-month referral order after appearing at Trafford youth court, then aged 17, in January on a separate matter.

The latest incident allegedly took place on 19 April, the day before Morrison helped United beat Chelsea to reach the FA Youth Cup final. Morrison was given conditional bail and the case was adjourned until 25 May, when he will enter a plea.

Morrison has represented England at every level from the Under-16s to Under-19s and has been described at Old Trafford as the most naturally talented footballer to come through the ranks since Paul Scholes. An attacking, two-footed player, he turned professional on his 17th birthday and made his first-team debut as a substitute in the Carling Cup tie against Wolverhampton Wanderers in October.

United are aware of the court case and have declined to comment. Morrison, described on the club's website as a "supremely gifted talent", was in the squad that travelled to Liverpool on Thursday for a reserve match. The club have dismissed rumours that he has been suspended, or is not training, and the teenager is still in contention to play in the youth cup final against Sheffield United. The first leg is at Bramall Lane on 17 May followed by the return fixture at Old Trafford on 23 May.

Morrison's court date is two days later and United face the possibility of losing one of the more prodigiously talented young players on their books.