"[Froome] should not be racing until there is a definitive conclusion to this, for better or for worse," Naesen told Sporza.
"You can't consider it a normal situation. This is very bad news for fans of the sport and its credibility. Hopefully the UCI will evaluate the defence's case soon."
Wellens last month outlined his opposition to the use of salbutamol inhalers in professional cycling, and he echoed Naesen’s point of view on Froome’s participation.
"His return has generated very different opinions," said Wellens, who came close to winning stage 2 of the Ruta del Sol on Thursday. "I wouldn't feel at all comfortable in Chris' situation and I would not have started to race until a verdict had been made public."
Other riders like Tony Martin (Katusha) and Philippe Gilbert (Quick-Step Floors), neither of whom are present on the Ruta del Sol, have said it would be better if Froome did not race.
"It's hard to give a view on it," Gilbert said. "But personally I think it's a big mistake because there is still doubt hanging over him and out of respect for the other riders, he should refrain from racing."
Froome himself, though, said that he had received a great deal of support from other riders in the peloton on stage 1 and that he had been "very touched" by their backing.
Froome's urine sample from an anti-doping control taken after stage 18 of the 2017 Vuelta a España was found to have twice the allowed limit of the asthma drug salbutamol. The 32-year-old says he is a life-long asthma sufferer, and insisted that he knows the rules and has never taken more than the permitted dosage.
The UCI rules do not require a provisional suspension in such cases, but some riders, team managers and race organisers have expressed concerns over Froome starting the 2018 season while the case was still pending as he would stand to forfeit any results and prizes should he be sanctioned over the case.