Randy de Puniet will sit out tomorrow's MotoGP test at Estoril after suffering leg pain during today's Portuguese Grand Prix.
The Pramac Ducati rider, who finished 10th despite the issue, had surgery in April to remove a screw inserted in his knee following his leg-breaking accident at the Sachsenring last summer.
"Before the start of the race, if I knew I'd finish 10th, I'd have celebrated the result this weekend," said de Puniet.
"But I don't know what happened with my knee. It hurt very badly in the race, and I didn't have enough strength in my legs.
"I had x-rays earlier this week, but I don't know how my ligaments are. I hope it's not anything serious, but tomorrow I will return home for a check-up.
"I'm happy for the six points earned, but without the pain in my knee, my result would undoubtedly have been better."