The Penrith Panthers have released promising speedster James Roberts after a string of alcohol-related off-field misdemeanours. The NRL's Integrity Unit is investigating.

Roberts, who won the Jack Gibson medal as the best player in the under-20's grand final last year, has been released from the first year of a new two-year contract but it is understood the NRL is in no rush to clear him to play for another club.

Released: Penrith have freed youngster James Roberts over a string of alcohol-related incidents. Credit:Wolter Peeters

Roberts was sleeping in his car when he joined the Panthers at the start of 2013 after he was released by South Sydney in 2012 for another alcohol-related misdemeanour.

It had been hoped Roberts had got his life back on track at the Panthers, but, despite enormous potential as a footballer, he was unable to fulfil his commitments at the club.