Andy Schleck is continuing to lose ground to his Tour de France rivals as his knee problems linger on. The 2009 Tour runner-up has had persistent problems in the joint this year and, according to the Luxembourg newspaper Wort, has been forced to head back home and undergo more treatment.

Schleck was originally due to start his season in the Challenge Majorca, running from February 11th, but had to scratch those plans due to the pain. He was told by doctors in Luxembourg to take a break from training and to work with physiotherapists, and duly did so.

He returned to Majorca last Tuesday, stating before the flight that he was feeling good. “[I’m] really happy, I got my knee pain-free and can get back on track,” he said on his Twitter feed, apologising for having to miss the Ruta del Sol.

The following day he said that he was able to ride without pain, but continued to feel some tenderness afterwards. Schleck returned to Luxembourg on Monday, having spent less than a week training on the island and, according to Wort, will now undergo alternative treatment to try to get to the bottom of the problem.

He stated before that he hoped to start his season in the Giro del Friuli, which takes place in exactly one week’s time. That will clearly now depend on how his knee responds to the latest treatment.

Schleck is likely to be concerned at the ongoing delays he is facing. Lance Armstrong, who finished just one minute and 13 seconds behind him in last year’s Tour, began racing over a month ago and has been training hard ever since. Alberto Contador, who beat him to take the yellow jersey to Paris, began his season last week in the Volta ao Algarve and won the mountain stage plus the final overall classification there.

In fact, every other rider in the top ten at last year’s Tour has started their season. Four of those have already taken victories; Contador had that impressive success in Portugal, Bradley Wiggins (4th in Paris) was part of the TTT-winning squad in the Tour of Qatar, Vincenzo Nibali (7th) won a stage plus the overall classification in the Vuelta a San Luis and Christophe Le Mével (10th) took the last stage plus the final GC in the Tour du Haut Var on Sunday.