The Briton was taken to hospital in Valencia for a precautionary scan, but plans to be back on track on Saturday.
"It's a shame I crashed this morning, because I had a good feeling with the bike and was going well," said the 20-year-old. "The crash was my fault, because on my out lap I went a bit slow and when I tried to force the pace coming onto the straight the rear tyre was still cold and the traction control wasn't able to compensate so I was launched up. Tomorrow I'll try to ride, and I hope I'm not in too much pain because now my hand and back are hurting pretty bad."
Team-mate Alex Barros, riding in what looks like being his last grand prix after a mammoth 21-year world championship career, was a much more promising seventh fastest.
"During the afternoon, we were able to improve the front and the rear a lot, for which I'm satisfied and confident for tomorrow morning," said the Brazilian. "Also, we have tried to find the best tyre, as far as durability, looking towards the race on Sunday. Concerning the engine, we continued to perfect small aspects of the power delivery, and have reaped the benefits, In addition, we're starting tomorrow with a fresh engine which will give me a little 'extra boost' and help me to lower my times so I can get a good spot on the grid during qualifying."
