Andrea Dovizioso says he is in "big pain" after crashing on day one of MotoGP's post-season Jerez test and will need his discomfort to be "acceptable" to ride on Thursday.
Dovizioso ended the penultimate day of 2018 running second-fastest behind new factory Ducati team-mate Danilo Petrucci.
But the Italian's day ended early with a crash at the Turn 5 right-hander and, while an x-ray revealed he did not brake any bones, he suffered swelling around the base of his left thumb.
"I have big pain, but it looks like there is not anything bad, that is the most important thing," said Dovizioso.
"I did an x-ray but they couldn't see anything [broken], but you never know - maybe there is a muscle or something, but nothing bad.
"If tomorrow [the pain] will be acceptable I will continue to test. We have something to compare. I hope I have a chance to do that."
Explaining the crash, Dovizioso added: "I was pushing, I wanted to improve the lap time.
"In that moment I had the experimental rear Michelin, already some riders did a lap time with that and it worked well, and we changed the set-up. We did a big step in one way, we wanted to understand.
"I tried with a used tyre, the feeling was good on the front [even] if the lap time wasn't so good, and I wanted to push with a new tyre to really put the bike on the limit. That was very important for us.
"But I was too fast in the middle of the corner. That set-up didn't work as well as my previous one in that moment.
"I was pushing really hard and I lost the front.
"Small crash, but when I got to the gravel I started to roll. I hit a lot of parts of my body."