Marcus Ericsson flew to Spa-Francorchamps as there was doubt over whether or not Raikkonen could drive this weekend.
Alfa Romeo has not commented on whether or not Raikkonen will be in the car past Friday, as it is likely that he will be evaluated by the team after the day's running.
“If you ask me the break could always be longer as I enjoyed time with my family a lot, but I’m also looking forward to be back in the car," Raikkonen said.
"I’ve just been told that I’m called ‘The King of Spa’ because I’ve won there several times, but that doesn’t mean anything to me.
"Yes, it’s my favourite track, but more important is that we work hard to get the best out of the car and continue our good run from the last races before the break.”
In 2013, Raikkonen missed out on two races at the end of the season as he underwent back surgery. Heikki Kovalainen replaced him on that occasion.
Bahrain International Circuit - Winter testing