Pascal Wehrlein says critics of his decision to miss the first two Formula One races of the season were not aware of the severity of his injuries as he prepares to make his Sauber debut in Bahrain.
The Mercedes junior driver was unable to race in Australia or China after injuring his back at the Race of Champions in January, with Antonio Giovinazzi taking his place on the grid.
Wehrlein's decision not to race split opinions in the paddock, with the German opting not to race in China in order to regain full fitness.
But the 22-year-old, who joined Sauber in the close-season, believes it was his only option.
"I don't care too much what the others say because they didn't know my situation and they were commenting on my situation," he told reporters in Bahrain.
"For me it was the right decision, together with [Sauber team principal] Monisha [Kaltenborn] and with [Mercedes boss] Toto [Wolff], and what the other drivers think is their stuff.
"If you don't know which injuries someone had then you shouldn't criticise them. It's quite simple: if the injury was just some muscle pain, do you think Sauber or Mercedes would accept me to not drive?"
On the extent of his injury, he added: "I fractured three vertebrae in the thoracic spine. I compressed quite a few, but three of them were fractured.
"Medical-wise, everything is good, it's just the muscles around, they went away, if you can't do sports for a few weeks, but they are rebuilding quite quickly as well. I'm quite positive.
"I couldn't move for quite a long time and of course I was restricted a lot in my training. I lost a lot of muscle, so that was the main focus, to rebuild those muscles."