The Pramac team has confirmed that Danilo Petrucci has broken several bones in his right hand, and will need further evaluation.
In a final test day that saw a total of 13 crashes, Petrucci's was by far the worst and will lead to him needing a checkup in Melbourne on Saturday.
The Italian rider took a tumble from his #9 Ducati and according to the Pramac team Twitter account, he has fractured the second, third and fourth metacarpal in his right hand.
Petrucci had been fastest in the wet first day of testing at the Australian track, which will host the 16th of the 18-round 2016 season.
It is not yet clear whether the 25-year-old Italian's injury will prevent him starting his fifth full season in MotoGP, albeit Pramac has ruled him out of participating in the final pre-season test in Qatar.
"The weather conditions did not help us with working on the set-up and Danilo's accident is too big a price to pay," said Pramac's Francesco Guidotti.
"It's never the right time to fall and hurt but surely this is a particularly sensitive time.
"We have to focus on Danilo's recovery. The whole team is with him. We are confident that he will recover soon: the hope is that he will be on track for the GP in Qatar but now is too early to have a clear scenario."
Petrucci scored the best result of his career at Silverstone last year, finishing runner-up behind Valentino Rossi in torrential rain.