Quinn Simmons' participation in the Tour of Flanders is in doubt.

Simmons fell ill after Tirreno-Adriatico earlier this month and missed finishing both Friday's E3 Saxo Bank Classic and Sunday's Ghent-Wevelgem.

"After Tirreno-I got sick and it was impossible to prepare here," Simmons told Cycling News in Wevelgem. 'I had to give 110% in order to be in the top group.'

Simmons contributed to the Trek-Segafredo team, helping leaders Jasper Stuyven and Mads Pedersen early in both races. However, this was far from his role earlier in the spring.

"It's nice to be able to help, but ultimately it helps the final. It's a little frustrating, but I owe it to them to do what little I can," Simmons said.

"I don't have a choice. If that's all I can do, that's all I can do. It's much more embarrassing to just sit in a group and do nothing. At least I was able to do a little bit. It wasn't much, but it was all I could do. Still, I emptied my few legs."

Simmons' recent illness and current poor form have jeopardized his Classics schedule, which includes Amstel Gold and Paris-Roubaix. Simmons, who was previously considered a certainty to compete in the Tour de Flanders, is now uncertain whether he will even compete on Sunday.

The 20-year-old will again compete in the Dwar do Hlaanderen on Wednesday.

"I will decide after Wednesday whether to ride or not. If I don't make progress by then, there's no point," Simmons said.

"Steven de Jong, the DS here, is also my coach, so we will decide together. Hopefully Wednesday will go well and we'll be in the race. If not, I will go back to Girona and do a little training to get ready."

"There is still Amstel and Roubaix. Roubaix is still three weeks away. It doesn't make sense to keep riding and then retire after another 100 km."