The Yamaha Factory Racing rider, who received surgery only two weeks ago for a broken collarbone sustained at Assen practice, was him smooth self, taking the top time at FP1 amid many crashes. But things drastically changed in the second free practice.Lorenzo suffered a high-speed crash in FP2, falling heavily on his damaged shoulder. X-rays showed he had damaged the plate inserted during surgery, and he was forced to withdraw from this weekend’s MotoGP. Yamaha reports Lorenzo will fly home to Barcelona Friday evening, and undergo additional surgery on Saturday.With Lorenzo out, it appeared the fastest times would turn to either his teammate Valentino Rossi, or one of the Repsol Honda boys, either Dani Pedrosa or Marc Marquez.But the only German on the 2013 MotoGP grid was the top rider – LCR Honda’s Stefan Bradl. The RC213V rider posted a best lap of 1:22.030. To put this time into perspective, the circuit record is a 1:21.846 recorded by Pedrosa in 2011.Of FP1 and FP2 combined, Bradl was 0.017 of a second quicker than Lorenzo, with Pedrosa 0.191 further back. Rossi was fourth quickest, 0.211 back, followed by Marquez, who was 0.211 behind.Taking the sixth through eighth quickest spots Friday was Monster Yamaha Tech 3’s Cal Crutchlow (-0.439), Ducati Team’s Nicky Hayden (0.542) and the top CRT rider, Power Electronic Aspar’s Aleix Espargaro (-0.611).Not surprisingly, Pedrosa followed Bradl, but was 0.209 of a second slower, and a mere 0.012 of a second quicker than his teammate Marquez. Though he crashed, Lorenzo was fourth quickest, 0.222 of a second back, with Rossi taking the fifth fastest time, 0.365 of a second behind.Lorenzo’s crash occurred just ten minutes into the 45-minute session. The reigning MotoGP Champion, who trails Pedrosa by seven points after finishing fifth at Assen 38 hours after surgery, lost control of his YZR-M1 at turn 10. The session was briefly stopped as crews looked over him.Jorge Lorenzo (Yamaha Factory Racing YZR-M1 MotoGP) says: “I have decided to go home and recover after today’s crash at Sachsenring. 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.”Just after the restart, Crutchlow suffered a crash at the quick turn 11. While sliding through the gravel trap, several pieces of gravel were lodged into his right glove. The rocks were removed by the staff at the Clinica Mobile, and his wounds cleaned up. Crutchlow is fit to ride tomorrow.Sadly for the struggling Ducati, both Ducati Team’s Andrea Dovizioso and Energy T.I. Pramac Racing’s Andrea Iannone crashed at the same corner. The riders were using the GP13 “Evolution” chassis, hoping for better results this season. Unfortunately for Dovi, the Italian will have to revert back to the regular GP13 chassis.Cardion AB Motoracing’s Karel Abraham was struck down with flu and fever and for that reason did not take part in the afternoon period. CRT’s Hiroshi Aoyama was back in action with Avintia Blusens for the first time since his hand-injuring crash on the Saturday of the Catalan Grand Prix. In Practice 2, GO&FUN Honda Gresini’s Bryan Staring added his name to the list of fallers, MotoGP reports.The grid will return to Sachsenring Saturday for the last two free practice sessions ahead of qualifying.