Trainer Luca Cumani hopes fellow Italian Frankie Dettori can put his six-month suspension behind him as soon as possible for the good of racing.
The three-times British champion jockey, 41, tested positive for what is believed to be cocaine following a routine examination at Longchamp on September 16.
Cumani gave Dettori his first job in British racing as an apprentice in 1985 before he went on to become the Newmarket trainer's stable jockey, enjoying great success together before Dettori moved on to become retained jockey to Sheikh Mohammed's operation Godolphin.
Cumani told Press Association Sport: "I'm sad that this has happened and hope it doesn't happen again. He is the best jockey that has been around for quite a while and a great ambassador for the sport.
"He has done a world of good to the sport and let's hope he can put this behind him quickly and go back to where he was."
The Professional Jockeys Association intend to look at the mental well-being of their members and give riders any support they might require.
Paul Struthers, PJA chief executive, said: "As in any walk of life jockeys will make mistakes. Frankie Dettori has made such a mistake and accepted the consequences of it, and if he needs any support the PJA and Injured Jockeys Fund between them can provide that.
"The wider issue of jockeys' mental well-being is something the PJA cares passionately about.
"As well as all the normal pressures that other sportsmen and women have to contend with, unlike many other sports jockeys have the added pressures of massively reduced calorific intake and are constantly at very real risk of serious injury.
"Jockeys in Great Britain have an excellent support structure in place in many respects. This is true when it comes to mental well-being, but whilst the support is there, racing perhaps lags behind other sports particularly when it comes to raising awareness of the issues and the support that is available, and it is overdue that more was done."
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