Casey Stoner is 'unlikely' to continue as a Ducati MotoGP test rider in 2019, the factory has confirmed to Crash.net.
The Australian, reaching the end of a three-year agreement with Ducati, is currently unfit to test following major shoulder surgery and looks set to step back from riding duties.
Michele Pirro is now expected to be Ducati's sole MotoGP test rider next season.
Ducati ruled out rumours of Alvaro Bautista taking over some of Stoner's test days next year, but could sign the Spaniard to ride for their factory World Superbike team in 2019.
After retiring at the end of 2012, with 38 MotoGP wins and a world title for both Ducati and Honda, Stoner initially conducted some testing for HRC (and an ill-fated Suzuka 8 Hours entry) before returning to Ducati in 2016.
The Australian has taken part in the start-of-year Sepang tests in 2016, 2017 and 2018 - leading the full-time field on the opening day in 2017 - plus occasional European tests and promotional work as a Ducati Ambassador, including a recent appearance at World Ducati Week.
However, the 32-year-old underwent major shoulder surgery on the Suzuka injury following January's Malaysian tests, and is not yet fit to return to the track.
Ducati told Crash.net that Stoner can't yet lift or rotate his right arm as required, despite having passed the four-month recovery time suggested by Doctors. As a result, further MotoGP tests that Ducati had planned for Stoner this year have been put on a hold.
A final decision on Stoner's future role at Ducati should be made in September.