Fernando Alonso had his day cut short in Bahrain on Wednesday as the chassis he was running was found to be damaged.
Entrusted with both days at the Sakhir circuit, Ferrari swapped Alonso's chassis for Kimi Raikkonen's on the second day of testing.
However, after just 12 laps the Scuderia discovered that the chassis had sustained more damage than previously thought in Raikkonen's FP1 collision with the Turn 4 kerb last Friday.
And although the Finn used the chassis for the rest of the Bahrain weekend, finishing 10th on Sunday night, Ferrari opted not to run after the damaged was discovered on Wednesday morning.
A spokesman told the BBC: "The kerb impact in FP1 caused some local damage which we repaired during the weekend, but it has now become clear that there was also some consequential damage, unseen over the remainder of the weekend.
"This damage became only apparent this morning, and we stopped running on a precautionary basis in order to fix the chassis."
Alonso finished the day down in eighth place, 5.776s off the pace set by Lewis Hamilton.
Gallery: Bahrain Test Day Two