Before going to hospital for checks, the Brazilian sat trackside with a neck-collar in the wake of his two high-speed crashes at Monaco's first corner last weekend.
Ferrari team boss Stefano Domenicali said earlier this week: "Felipe is fine.
"All he has to show for (the crashes) is a bit of muscle pain."
Indeed, on Thursday Massa tweeted a photo of himself training at home with the caption: "Working hard, 100pc confident for the race".
Williams' Pastor Maldonado also crashed heavily during the Monaco grand prix, his clash with Max Chilton bringing out the red flags when it dislodged the soft barriers.
"My body still hurts," he told The Racer's Edge, "but it's not a problem.
"As soon as I knew I was ok I was thinking already of Montreal."