Simmons fell ill after Tirreno-Adriatico earlier this month and was a non-finisher at both E3 Saxo Bank Classic on Friday and Gent-Wevelgem on Sunday.
"I was sick after Tirreno, and that's no way to prepare here," Simmons told Cyclingnews in Wevelgem. "You have to be at 110 per cent here just to be in the front group."
Simmons has been able to make contributions to his Trek-Segafredo team, helping position leaders Jasper Stuyven and Mads Pedersen in the early phases of both races. However, it's a far cry from the role envisaged for him ahead of the spring.
"It's nice to be able to help but in the end I'm supposed to be there to help in the final - not in the first 100k. I'm a bit frustrated but I owe it to them to at least do what little I can," Simmons said.
"I don't really have a choice. If it's all you can do, it's all you can do. It would be a bigger shame to just sit in the bunch and do nothing. At least I could do a small bit. It's not much but it was all I had. I still emptied what little legs I had."
Simmons' recent illness and his current lack of form have placed his Classics schedule - which also includes Amstel Gold and Paris-Roubaix - in doubt. Previously a shoo-in for Tour of Flanders, the prospect of him riding on Sunday is now uncertain.
The 20-year-old will line up again at Dwars door Vlaanderen on Wednesday, which should provide the definitive verdict.
"We'll make the decision after Wednesday whether I ride or not. If I don't progress by then, then it doesn't make sense," Simmons said.
"Our DS here, Steven de Jongh, is also my coach, so it's a decision we'll make together. Hopefully, Wednesday goes well and then we can race. Otherwise, I'll go back to Girona, train a bit and get ready.
"We still have Amstel and Roubaix. Roubaix is still three weeks out still. It wouldn't make sense if I continue to ride like this to do another 100km and then pull out."
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Deputy Editor - Europe. Patrick is an NCTJ-trained journalist who has seven years’ experience covering professional cycling. He has a modern languages degree from Durham University and has been able to put it to some use in what is a multi-lingual sport, with a particular focus on French and Spanish-speaking riders. After joining Cyclingnews as a staff writer on the back of work experience, Patrick became Features Editor in 2018 and oversaw significant growth in the site’s long-form and in-depth output. Since 2021 he has been Deputy Editor - Europe, taking more responsibility for the site’s content as a whole, while still writing and - despite a pandemic-induced hiatus - travelling to races around the world. Away from cycling, Patrick spends most of his time playing or watching other forms of sport - football, tennis, trail running, darts, to name a few, but he draws the line at rugby.