Ferdinand is fighting the charge of 'failure or refusal to submit a drugs test' on 23 September.
The United boss was part of a formidable list of witnesses seen by the three-man commission today as Ferdinand's legal team mounted a spirited defence.
United club doctor Mike Stone and Manchester City's Eyal Berkovic were also at The Reebok to give evidence. Nicky Butt arrived at the hearing at midday as he was one of the other United players chosen for a drugs sample alongside Ferdinand. Butt did oblige but Ferdinand's team believe his evidence may throw doubt on testing procedures.