Everyone saw the maths yesterday - Sagan has the green jersey sewn up and with the largest margin historically. He just needs to make it to Paris.
But in the blink of a 65 kilometre stage, fortunes can change. Losing contact with the lead group but not needing any more points in the green jersey competition, Sagan perhaps needlessly pushed too hard on the descent of the Col de Val Louron-Azet.
Thankfully, the Slovakian made it back on to his bike and to the finish in Saint-Lary-Soulan where further tests revealed nothing was broken. Sagan feels confident about continuing the race.
But the team said in a statement it will decide in the morning about Sagan starting Stage 18 and if he can continue on to Paris and claim his sixth green jersey.
*Gross out warning* - meanwhile, Philippe Gilbert posted this update about his Tour de France ending injury.