Controversy and mystery continue to surround Bradley Wiggins’ (Sky) participation at this year’s Tour de France.

Having previously been told by his team that he must ride in the service of team-mate Chris Froome in the French Grand Tour, it appears that defending champion Bradley Wiggins might end up missing the event altogether this year. According to British media reports, the Team Sky rider continues to suffer from health issues which plagued him during the recent Giro d’Italia and has not been able to prepare correctly for the race as a consequence.

Wiggins entered the race as the main favourite but was clearly out of sorts in the Giro. He crashed on stage seven, lost time on several of the wet descents and was also dropped on the ascents. The latter part of the first individual time trial was in fact the only time during the Italian Grand Tour that Wiggins shone. He developed inflammation to his left knee and also a chest infection, and eventually abandoned the race.

The general perception has been that Wiggins would return for the Tour de France, but last year’s winner has not been included in the Sky line-up for the upcoming Critérium du Dauphiné, which begins this weekend. The news that he may miss the Tour de France was revealed yesterday by the Daily Mail. Today, Team Sky principal Dave Brailsford has confirmed that question marks do linger about Wiggins’ Tour participation.

“With these setbacks I can confirm that Brad cannot currently train properly and we are monitoring this situation carefully,” he told the Guardian.

The paper also indicates that Wiggins’ knee issues may be due to too much play in his pedal.

Wiggins dominated last year’s calendar, taking victories in Paris-Nice, the Tour de Romandie and the Critérium du Dauphiné before winning the Tour de France. He finished three minutes 21 seconds ahead of Froome, who looked stronger than him on some of the mountain stages but lost time in the race against the clock.

Wiggins also went on to win the Olympic time trial, with Froome taking third.

As the defending champion, Wiggins said at the Tour presentation last October that he didn’t intend to target a repeat win, but would instead focus his energy on the Giro.

Since then he has changed his position on several occasions. In late April Wiggins told the BBC that he wanted to go for the Tour. “The Tour de France is my focus,” he said then. “It's just that I'm doing the Giro before." Subsequently this statement drew a heated response from Froome and later an official announcement from the team established Froome’s credentials as team leader at the Tour.

Now it would seem that Wiggins might not even start the race, which begins in Corsica on June 29th.