Bardet began stage 13 of the race in fourth place overall, 14 seconds off Juan Pedro López (Trek-Segafredo), and well within reach of finishing on the podium.
In a shocking turn of events, with roughly 115km to go, Bardet fell back to the rear of the peloton.
Not long thereafter, the pink jersey contender came to a halt, succumbing to his illness.
Bardet’s withdrawal from the Giro d’Italia is a devastating blow to the rider’s chance to etch a Grand Tour on his record.
Despite the disappointment, the team rallied together, and Stage 12 winner Alberto Dainese sprinted to a commendable fifth place on stage 13 behind winner Arnaud Demare (Groupama-FDJ).
“It was really sad that we lost Romain today and after he stopped, we tried to regroup a bit and ride together,” said Dainese post-race.
“We put a couple of guys in the chase behind the breakaway to help control the gap and bring it back. It was super close at the finish and I went for it in the sprint but today I could only manage fifth.”
While DSM have lost their GC leader in Bardet, and sprinter Cees Bol hasn't been in top form, the emergence of Dainese and some strong team performances means there's still much to fight for in the remainder of the race.
“It’s really disappointing but we have a great team here and I’m confident they will continue this Giro in a good way with great spirit and hopefully some more good results,” said Bardet following his withdrawal.
