His former manager at Endura, Brian Smith, also gave his backing.
Tiernan-Locke has been asked by the UCI to explain possible discrepancies in his blood values between the latter part of 2012 and beginning of 2013. Brailsford said that it was possible there was an innocent explanation for any discrepancy.
"He hasn't failed anything yet or there's nothing where you would say, 'This is something which needs to be addressed'," Brailsford said. "It appears there's an anomaly which needs to be looked at and explained. This isn't the first time that this has occurred.
"We've got to allow them to carry on with the process, get both sides of their appropriate roles done, try to establish the truth - which is the important thing. Once we have the truth, we can all deal with that and go from there."
Before signing with Sky, Tiernan-Locke had a remarkable season with the Endura team, winning the Tour du Haut Var and the Tour Mediterranéen, where he took two stages, and going on later in the year to win the Tour of Britain. "I can't explain any of the irregularities but I would definitely vouch 100% for John," said Smith. "For me, I don't know how he's going to explain this to the UCI but I don't think he should have anything to worry about. I can put my hand up though and say 100 per cent that I don't think he was doping at Endura Racing. There was no suspicion, no nothing."
As first-tier teams such as Garmin and Sky showed interest in Tiernan-Locke, he was tested by the former and attended a Sky camp. "[Garmin team manger] Jonathan Vaughters got in contact and said there were no abnormalities in John's test and that they'd still like to progress with a possible chat of taking him on," said Smith. "Then Sky approached him and took him to a training camp in Tenerife at the start of May. As far as I'm concerned Sky showed all due diligence in looking after him."
Tiernan-Locke was rostered to ride for the British team at the world road championships at the weekend, but was withdrawn before the race started. Rod Ellingworth, the Great Britain team manager, criticised those who did take part following the disastrously unsuccessful road race.
Not one of the eight-strong British team - including big names Chris Froome, Sir Bradley Wiggins and Mark Cavendish - finished the 272.5-kilometre elite men's race on Sunday amid treacherous conditions in Tuscany.
Asked if he felt his riders lacked spirit, he said: "Yes. I think it may be that simple. A lot of people were talking the talk beforehand and didn't see it through. No excuses, each and every one of them underperformed.
"After the success we've had in previous years this was a very poor result. Having the British jersey on their backs, they should be disappointed. They didn't show what they are capable of."