Joan Mir will miss MotoGP’s Japanese and Indonesian Grands Prix as Honda carries out further medical investigation after health symptoms and extreme fatigue at the San Marino Grand Prix. Honda HRC Castrol has confirmed that Somkiat Chantra will replace Mir at Motegi.
Honda said Mir was continuing a recovery and observation programme after medical concerns first emerged following the San Marino weekend. The 2020 MotoGP world champion withdrew from that event after experiencing extreme fatigue and then missed the Austrian round while undergoing further checks, according to specialist reporting.
The manufacturer said detailed medical analysis had identified altered blood-test parameters requiring further investigation. Autosport MotoGP reported that Mir’s doctors had advised him to prioritise recovery and further examinations because a clear diagnosis had not yet been established. Honda said it would next update Mir’s condition after the Indonesian Grand Prix.
Mir will therefore be absent for the two-race sequence at Motegi and Mandalika. The confirmed absence means Honda must use a substitute at Motegi and appoint another replacement for Mandalika, where Chantra has not yet been confirmed.
Chantra returns for Honda’s Motegi round
Chantra has been officially named for the Japanese Grand Prix only. The Thai rider competed for LCR Honda in MotoGP during 2025 before joining HRC’s World Superbike programme for 2026, and his selection returns him to the premier class at a circuit with particular personal relevance.
MotoGP reported that Chantra won the Moto2 race at Motegi in 2023. He also finished 15th there in MotoGP with LCR Honda in 2025. Honda’s announcement described him as Thailand’s first MotoGP rider and said he had scored World Superbike points on seven occasions this season after recovering from pre-season injuries.
The call-up was shaped by Honda’s available options at Motegi. Takaaki Nakagami substituted for Mir in Austria, but he cannot remain in that role in Japan because he is already entered as a wildcard for the Honda Test Team. Specialist reports said Nakagami will run his own programme at his home event rather than take Mir’s factory-team seat.
Honda has therefore turned to Chantra, who has recent MotoGP experience and established knowledge of the Motegi circuit. The arrangement gives the factory team a replacement who has raced Honda machinery in the championship, although Chantra has spent the current season competing in World Superbike.
Indonesia replacement remains unresolved
Chantra’s involvement beyond Japan has not been confirmed. Autosport MotoGP reported that the Indonesian Grand Prix clashes with the World Superbike round at Estoril, scheduled for 9-11 October, where Chantra is due to have commitments. Honda has consequently not announced who will replace Mir at Mandalika.
That distinction is important in assessing Honda’s announcement. The team has confirmed Mir’s absence from both races, but it has confirmed Chantra only for Motegi. Its choice of a second substitute remains open rather than having been settled by the Japanese Grand Prix announcement.
| Rider | Status for the upcoming rounds |
|---|---|
| Joan Mir | Ruled out of the Japanese and Indonesian Grands Prix while further medical investigation continues. |
| Somkiat Chantra | Confirmed to replace Mir for the Japanese Grand Prix at Motegi. |
| Takaaki Nakagami | Entered as a Honda Test Team wildcard at Motegi, so unavailable to substitute for Mir there. |
| Indonesia replacement | Not confirmed by Honda. |
A disrupted spell for the factory team
Mir’s withdrawal removes a former world champion from Honda’s works line-up at Motegi. Honda will field Chantra there, then must make a separate replacement decision for Mandalika because Mir is confirmed to miss both rounds and Chantra’s World Superbike schedule overlaps with the Indonesian weekend.
For Chantra, the opportunity is limited in scope. His Moto2 victory at Motegi in 2023 and his MotoGP appearance there in 2025 provide relevant circuit experience, but Honda has made no announcement that his Japan call-up will extend to Indonesia. The Estoril clash is the reported complication.
Mir’s recovery remains the central issue. Honda’s planned update after the Indonesian Grand Prix identifies the next point at which the team expects to provide further information, with the rider continuing the programme recommended after his medical assessments.