Takaaki Nakagami has been ruled out of this weekend's Thailand MotoGP round following the discovery of a torn tendon in a finger.
The Japanese rider will undergo further surgery this Friday, with compatriot Tetsuta Nagashima to take his place on the LCR Honda Idemitsu entry at Buriram.
Nakagami was injured two rounds ago at Aragon when he was hit by Marc Marquez, who was struggling to control his own Honda after it incurred damage in contact with Fabio Quartararo.
The LCR rider gritted his teeth through his home grand prix at Motegi, days ago, but was the last finisher in 20th position, nearly 14 seconds behind Remy Gardner, who took the chequered flag in 19th after 24 laps of racing.
Nagashima also started that race, making his premier class debut on an ‘HRC Team' wildcard entry in what was essentially a reward for helping Honda to win August's Suzuka 8 Hours, but crashed out on Lap 10.
“First of all, I wish Taka well and I hope that he can come back as soon as possible,” said Nagashima.
“I will try to do my best in his place for the LCR Honda Idemitsu Team and I will try to enjoy the racing.
“I'm looking forward to this weekend's event. I really had a lot of fun at the Japanese GP, and I learned quite a lot.
“So, this weekend, I want to continue to do the same because I still have to learn a lot of things with the MotoGP bike.”
Nakagami is not the only regular who will be missing at Buriram, with his future Honda stablemate Joan Mir still sidelined following another MRI after his highside at the Red Bull Ring.
Mir will be replaced at Suzuki Ecstar by two-time MotoGP race winner Danilo Petrucci, who has been granted permission to take the ride by Ducati, for which he now competes in MotoAmerica.