London - Chris Froome said on Tuesday that he was "surprised" by doping revelations concerning Bradley Wiggins, saying he did not know if his British rival was operating in a "grey area".
British cycling great Wiggins has been in the spotlight since leaked medical data showed the five-time Olympic champion had been granted a therapeutic use exemption (TUE) by cycling authorities for the powerful corticosteroid triamcinolone.
He was permitted to take the drug just days before the 2012 Tour de France, which he won, as well as the 2011 Tour and the 2013 Giro d'Italia.
Wiggins said he needed the drug to help control his asthma.
He came under fresh scrutiny following a report earlier this month in Britain's Daily Mail that United Kingdom Anti-Doping wanted to question him and his Team Sky bosses over a medical package delivered to the British outfit ahead of the 2011 Tour de France.
Both Wiggins and Sky boss Dave Brailsford, the British Cycling performance director until April 2014, have insisted they have done nothing wrong. The TUEs were also approved by the UCI, cycling's world governing body.
Froome, a former team-mate of Wiggins, also had his TUE history published by the hackers, although in his case the details were already known.
Asked about Wiggins's TUE use, Froome told cyclingnews.com: "I was surprised, it was the first that I had heard of them.
"I had seen Bradley Wiggins using his inhalers so I knew he had asthma, but I wasn't aware of his allergies.
"Without knowing the exact details of his medical condition, it's impossible to say if he was operating in a grey area."
Froome's two TUEs were for short courses of prednisolone, a steroid used to treat acute chest complaints, in 2013 and 2014.
The latter TUE provoked controversy at the time, as it helped Froome take part in a key Tour de France warm-up race in Switzerland, despite being ill a week before.
Cyclingnews.com said it asked Froome the difference between the TUE cases and the 31-year-old, replying in an email, said: "This is the standard treatment for post-infection inflammation in asthmatics that cannot be controlled by standard inhalers.
"I don't believe that there are any alternative treatments, and performance enhancement is negligible.
"With regards to Wiggins' TUEs, questions remain over his symptoms, the choice of treatment and the related performance benefits from that treatment."