MotoGP champion Jorge Lorenzo has been forced to withdraw from this weekend's Sachsenring round after damaging the titanium plate holding his broken left collarbone together.

"I have decided to go home and recover after today's crash at Sachsenring," said Lorenzo.

"I prefer to focus on surgery to fix the plate that was unfortunately bent during the crash. I will try to recover and be back as soon as possible."

Lorenzo suffered the original injury at Assen, underwent surgery in Barcelona, then made a shock return to claim fifth in the Dutch race.

Having had two weeks to heal, the German MotoGP began in perfect fashion for the Yamaha star when he was fastest in morning practice. Lorenzo was again leading early in the afternoon session - when he was thrown into the air at turn ten (pictured) and landed hard on his injured shoulder.

"The diagnosis after the fall is that the osteosynthesis material is bent in the middle," said Doctor Enric C?ceres. "The screws of the proximal and distal have endured but Jorge will need a new intervention to re-attach the clavicle, because the plate has been curved slightly."

Lorenzo sprung to his feet after the incident but was soon reaching for his collarbone and headed straight to the Medical Centre for X-rays. The plate and eight screws had been required to stabilise the 'displaced, complex fracture' suffered at Assen.

The Spaniard will now return to Barcelona for a second round of surgery on Saturday, after which it will be decided if he is fit to try and ride in next weekend's US GP. The summer break then begins, followed by the Indianapolis round in mid-August.

"Second practice here in Sachsenring has gone wrong like in Assen. This morning fastest and this afternoon a fast crash on maybe the second or third lap. Again he has hit the left shoulder and the plate has been bent," confirmed team manager Wilco Zeelenberg. "It's obviously very painful so we need to consider and step by step decide what the plan is for the coming days."

Lorenzo is just nine points behind Dani Pedrosa after his Assen heroics.

However Pedrosa, who finished one place ahead of Lorenzo in Holland, has won the last three German GPs and will be eager to make the most of an unexpected second chance to build a big points lead.