Kimi Raikkonen was well enough to return to the Lotus cockpit for the final day of 2013 Formula 1 winter testing at Barcelona on Sunday after missing day three of the test due to illness.
The Finn had been scheduled to take over from Romain Grosjean for Saturday and Sunday.
But he was struck with suspected food poisoning and had to take Saturday to recover.
Grosjean had already left the track, so reserve driver Davide Valsecchi was called up to begin running for Lotus until the Frenchman made it back to Barcelona.
Lotus team boss Eric Boullier said on Saturday night that Raikkonen was expected to be fit enough to drive on Sunday, and he duly took to the track when the session began.
Grosjean remains on standby to take over in case of further problems.
09:13 Raikkonen has only done one installation lap. Vettel has completed eight laps, but all have been in or out laps.
09:58 And this explains why Raikkonen hasn’t recorded a time:
@Lotus_F1Team Though Kimi is fighting fit, the E21 has a little gearbox sniffle. Kimi’s having a quick nap as we apply Vix vapour rub to the box
10:56 An update from Lotus:
@Lotus_F1Team We think the gearbox has picked up Kimi’s bug so we’re drafting in a replacement. Fortunately, it doesn’t need to be flown in from Paris