The FIA has cleared Fernando Alonso to return to action at the Chinese Grand Prix, but the Spaniard must undergo another medical examination after the first practice session on Friday.
Alonso missed the Bahrain Grand Prix due to the injuries which he sustained in a high-speed crash in Australia but McLaren applied for Alonso to return in China.
Following a medical check-up on Thursday in Shanghai, Alonso has provisionally been cleared to participate in this weekend's Grand Prix.
"Back to the car," Alonso posted on social media. "26 days of resting initially and hard work until now. Thank you all for the support, also to my family, doctors, trainers and close friends. Now let's do it!"
However, following the opening 90-minute session on Friday morning, Alonso must once again be assessed in order to receive the green light to participate in the remainder of the weekend's action.
Reserve driver Stoffel Vandoorne, who scored a point on his debut in Bahrain, is on standby once more.
Full FIA statement:
"Since the accident at the Australian Grand Prix, McLaren driver Fernando Alonso has been undergoing the process of 'Reintegration' in accordance with Chapter II of Appendix L of the International Sporting Code.
"McLaren Honda have applied for Alonso to participate in the 2016 Chinese Grand Prix.
"As the injury to the driver was discovered some days after the Australian Grand Prix, the Reintegration does not strictly fall within the text of the Appendix.
"Therefore, the Stewards have taken advice from the FIA Medical Delegate, who in consultation with the Chief Medical Officer (CMO) of the Chinese Grand Prix and the driver’s doctors advise that he considers the driver provisionally fit to take part in the event.
"Given the exceptional circumstances, and having heard from the team, the Stewards have decided to exempt the driver from strict compliance with Art. 3(b) of Chapter II of Appendix L, relying instead on Art. 3(a) which has been satisfied.
"Therefore driver Fernando Alonso will be allowed to participate, subject to the provision below:
"The driver has been given directions by the FIA Medical Delegate and CMO which he is to follow (Art. 12.1.1.i of the International Sporting Code.) Further, in accordance with Art. 22.14 of the Formula One Sporting Regulations, he is instructed by the FIA Medical Delegate and CMO to undergo a further examination immediately following FP1 to determine his further eligibility to take part in the remainder of the Event."