Sauber driver Sergio Perez said he felt no ill effects on his return to the track in Valencia following illness.
The Mexican sat out the last race in Canada as he was feeling unwell following a heavy collision with a safety barrier during qualifying for the Monaco Grand Prix on 28 May.
But after returning to practice at the European Grand Prix, he said: "Everything went OK, I feel well.
"More than anything I'm happy to be back in the car."
The 21-year-old, who has impressed in his debut season, had said in the lead up to the European Grand Prix he was "more motivated than ever and looking forward to being back".
Veteran Pedro de la Rosa, McLaren's reserve driver, had been on stand-by to replace Perez if necessary, as the 40-year-old did when the Mexican felt unwell in Montreal.
“I have done a lot of work over the last weeks to get there [and] more than anything I'm happy to be back”
But the Spaniard was not needed as Perez was cleared to take a full part in both first and second practice in Valencia.
"I have done a lot of work over the last weeks to get there," he said.
"I picked up speed quite quickly and this is good."
Perez spent two days in hospital after being concussed in a heavy crash during qualifying for the Monaco Grand Prix.
He took part in first practice in Canada two weeks later but then withdrew from the rest of the weekend after complaining he felt dizzy, especially when braking and changing direction.
De la Rosa took over from second practice and finished 12th, while Perez watched the race at home in Mexico.