Andrea Iannone could return to the MotoGP grid in Aragon on a weekend of comebacks.
Iannone sat out the San Marino GP last time out after suffering a fractured vertebra in the first practice session at Misano.
The Italian has been cleared to return to his machine this weekend, although he will only do so if he feels confident in his fitness.
The 27-year-old said: "The problem is the pain. When I use this part of the body I have a lot of pain. So I don't know.
"Tomorrow we'll try our best and we'll understand the situation better, but I'm not making any promises because I'm not going to ride just to ride."
Iannone led a four-five finish for Ducati at Motorland 12 months ago, but a renewed ability to challenge at the front of the grid means such a finish could be classed as a disappointment for Ducati this time around.
Team-mate Andrea Dovizioso is also nursing injuries heading into the weekend, while Iannone's return coincides with Loris Baz's attempted comeback from injuries suffered in a horror crash at Silverstone two events ago.
Yet to be cleared, Baz will be at the track for the weekend, having suffered foot fractures in his first-lap shunt with Pol Espargaro at the British GP.
Completing the comeback theme is Nicky Hayden, the 2006 MotoGP champion, who will return to the grid for the first time this season as a replacement for the injured Jack Miller at Marc VDS.