Mathieu van der Pol has indicated that he will abandon the Tour de France if he doesn't see signs of improvement soon after suffering on the long road to Longueuil.

The Dutch star has been below his swashbuckling best in this Tour, and his troubles have intensified in the last couple of days. Van der Pol, who finished fifth in the opening time trial and assisted in the sprint of Jasper Philipsen, looked to be in front on the cobbles on Wednesday, but he fell off the bike with around 50km to go.

On Thursday, the situation was even worse, as Van der Pol temporarily lost contact with the peloton after a hard start to stage 6. He spent the rest of the day at the tail end of the peloton, just hanging on.

According to Dutch broadcaster NOS, "It was a very long day for me," van der Pol said. "Many times I wanted to give up. It was not a good day and I have nothing to add about it."

There is a general sense of confusion about the cause of van der Pol's ordeal. His father, Adly, revealed on Thursday that he tested negative for COVID-19.

Van der Pol started the Tour de France after the Giro d'Italia. It was his first career Grand Tour finish.

"I knew the Giro and the Tour would not be an easy combination, but I also did not expect such a setback," van der Pol said.

His father wondered if the month-long gap between the two events had been handled as well as possible. Van der Pol took a short break before ramping up his training again with a high altitude camp in Italy.

"If there was a mistake, was it a mistake?" Alpecin Phoenix director Christoph Rudhoeft told NOS. We tried to do our best, but at this point it is not working as expected."

"When he came into the Tour, we knew he wasn't at the top, but we thought a few quiet days would help him feel better on the bike.

"But of course, one thing follows the other. A bad run will affect his morale. In the long run, it's a vicious cycle. It's hard to figure out why that happens."

"It's not easy to figure out why.

The question is how much Van der Pol will continue to suffer in this Tour de France. His instinct is to keep riding, but he has indicated that he may abandon on Friday if he doesn't get the chance.

"I'll keep trying against my better judgment. Hopefully I'll improve. If I had stopped [on Thursday], I would have sat at home for two days and regretted it."

"I want to keep trying for a while. But if I'm still like this tomorrow, I'm not going to try one more day. This doesn't make sense either. If you are the first one to be dropped on a flat stage, of course something is wrong."