The Williams driver felt sick and dizzy during Friday running and was subsequently replaced by reserve driver Paul di Resta from qualifying onwards.

Massa stepped down form his duties in the post-Hungarian GP test, having flown home to recover.

Motorsport.com understands he suffered an inner ear issue but following a series of thorough medical checks, he was given the all-clear by his doctors.

"Actually I had a vertigo – so I was feeling dizzy not only in the car but also when lying down in the bed," Massa explained.

"I feel good. I feel ready to get back in the car. I had a… I was feeling a bit dizzy that weekend, vertigo is what I had.

"It was first time I had this strange feeling, it unfortunately happened in a race weekend and it kept me out of the car, I feel good now and ready to get back to the second part of the season, and hopefully we can do good races."

Massa, who continued training over the summer, then informed the team that he was ready to get back in the car for this weekend's race.

To compete at Spa, Massa required approval by the FIA medical delegate, as is standard procedure having missed the previous race.

That approval was given, following a test in the Belgian Grand Prix paddock early on Thursday afternoon.

Should Massa suffer a recurrence of the illness that he encounter in Hungary when he drives the car in Friday, di Resta will be drafted in.