The reigning world champion left the track at turn one, and his team feared that the vibrations from the resulting flat-spotter tyre would cause him to retire from the race.
During the early safety car period, Mercedes had a chance to pit hamilton to change the tyres, but the team opted to leave him out to give him a better chance of winning the race, at the risk of him retiring.
"With all the bad luck Lewis has had throughout the season, he got some of that back, some of the good luck back, because he badly flat-spotted the tyre," said team boss Toto Wolff. "The vibration matrix was scary from the beginning. We had quite a conversation on the radio about whether we should pit him for safety reasons."
"In any other race we would have pitted him and lost the race," he admitted. "We kept him out there in order to not throw away the championship for him. Every single lap, every single straight, we monitored the vibrations."
"Our team did a fantastic job in keeping that under control and then we pitted him a bit earlier because the vibration matrix was going sky high and a suspension failure could have easily happened," Wolff said.
Bahrain International Circuit - Winter testing