Suzuki's Joan Mir admits his huge Brno test crash in August led to him having problems breathing in some MotoGP races later in the 2019 season.
He returned at Misano and managed a top eight finish, before going on to finish the year as the second-best rookie in 12th in the standings.
But Mir revealed in Valencia that he struggled to breathe in the Malaysian and Thailand races, and says doctors told him his injuries will likely need six months to fully heal.
"I struggled [in races], but not here," Mir said at the finale in Valencia.
"I struggled in Malaysia because when the temperature and humidity is really high, I struggle to breathe more than normal.
"At the end, for Valencia, this was not a problem, [nor] for Australia or Japan. But for Thailand and Sepang, yes.
"Now we have time to recover. The doctors say this injury also probably needs six months to recover.
"I need more time to get ready to 100% because I had the injury, then straight away we had the Misano race and we never stopped.
"The break will be really good for me."
Mir managed nine top 10 finishes in his first year in MotoGP and summed up the year by saying he had "potential, but bad luck".
He added that both himself and Suzuki often had the pace "to fight for the top three", but that he was hindered by lacklustre qualifying performances.
"Difficult season because of injuries, one big one," added Mir, who only qualified on the front three rows five times in 2019.
"At the end I will say [we had] potential, but bad luck. This is what I would say about this season.
"We showed in a lot of practices, even in the races, that our pace was [there] to fight for the top three.
"But, then we always [had to] come from [further] back and, in this category, we are all really close and to make a difference, it's always really difficult.
"This is what we have to improve."
Autosport has produced a standalone special magazine to celebrate our 70th birthday. All current print subscribers will receive a copy for free. To order your copy of the 196-page Autosport 70th Anniversary issue, please go to: autosport.com/autosport70th