London - Bradley Wiggins' preparations for the defence of his Tour de France crown have been hampered by a knee injury that is preventing him from training properly, Team Sky principal Dave Brailsford revealed on Friday.
The British cyclist's challenge at the Giro d'Italia faded after he was hit by a chest infection and a knee problem.
Wiggins is scheduled to ride in support of Team Sky leader Chris Froome in the 100th edition of the Tour de France, which starts in Corsica on June 29, but Brailsford says he is currently short of fitness.
"With these setbacks, I can confirm that Brad cannot currently train properly and we are monitoring this situation carefully," Brailsford told British newspaper The Guardian.
Wiggins was not included in Team Sky's squad for the Dauphine Libere, which begins in France on Sunday.