Ignite Ducati's Ben Spies has revealed the full extend of the shoulder injury sustained when he crashed heavily at Sepang, ruling him out for the rest of the 2012 MotoGP season.

The Texan rider, who lines up at Austin for his home race on Sunday, missed the Valencia test and first swung his leg over the Demsosedici at the same circuit where he crashed but was still far from fit.

"I pretty much completely destroyed my shoulder and they had to do a full joint shoulder replacement, using a couple of cadaver tendons. It was a more of a major surgery than I initially thought. It happened in late October and I am still coming back," said Spies, speaking to our friends at Speed City, Austin.

"I'm not quite 100 per cent and I wish I was for my home race and able to tackle the weekend in a different way. We are doing the best we can, it is getting better and better. This is the worst injury I have had to come back from in terms of rehab. It's taken a while and we can only do it step by step and we will keep going forward.

"Right now I can't ride the bike like I want to. The Ducati likes to be ridden a little bit looser and more wild. I can't be quite as aggressive as I would like to be. I have had to smooth things out so I can make the race distance. We just did our first race and before that, the longest stint I had done was six laps. A race is 22 laps so that was the first goal."

Click here for the full podcast