As per the rules of MotoGP, a replacement rider needs to be set for an injured rider once a set time period elapses. Just as with Rossi's replacement being ready at Aragon, Honda have to replace the injured Jack Miller at its home race, and they've settled on Hiroshi Aoyama.
Aoyama is a former 250cc world champion and has been a test rider for the Honda MotoGP team since 2015. Prior to that he spent four seasons racing in MotoGP. He is one of the top riders at HRC in the MotoGP project - meaning that jumping onto the RC213V at his home track should mean that the only rust will be that of racing. As always, though, test riders usually take a little time to get up to the rigours of a day at the races - but a new rider in the mix is always good news for the sport.
Given Valentino Rossi's return timeline from his injury, which was very similar, we can reasonably expect Miller to make it back to the series in time for his home race, the Philip Island round, on 22 October.