Sprinter Christian Coleman cannot be the face of athletics following the controversy over his missed drugs tests, says US legend Michael Johnson.
The 23-year-old American is the fastest man in the world over 100m this year.
"It completely disqualifies him, at this point, from ever being that face of the sport. This will follow him, as it should," Johnson told BBC Sport.
"I think this is an incredibly important issue around the sport because Christian Coleman was being touted to replace Usain Bolt as the big star of the sport.
"I don't think that will happen now as a result of this. I think that fans of athletics don't have any tolerance at this point for any sort of doping infraction."
Coleman is world indoor champion over 60m and won silver in the 100m at the last World Championships in London two years ago. His 9.81 seconds in the 100m at the Diamond League in California in June is the fastest time in the world this year.
In response to the controversy, he has said he has "never failed a drug test and never will".
"It's simply disrespectful when fake fans speculate and talk about drugs in relation to the great athletes we have in this sport," wrote Coleman on social media.
"It does nothing but hold the sport back from the popularity I know it can reach in the future."
What was Coleman accused of and why was charge dropped?
The US Anti-Doping Agency (Usada) said Coleman had missed drugs tests on 6 June last year, and 16 January and 26 April this year - with three missed tests in a 12-month triggering an automatic one-year ban.
However, the charge against the American was withdrawn after Usada received guidance from the World Anti-Doping Agency (Wada).
The International Standard for Testing and Investigations (ISTI) says a "filing failure" - failing to update details of the athlete's daily whereabouts - should be deemed to have occurred on the first day of the quarter, so Coleman argued the first of those failures should be marked down as 1 April, 2018, meaning he did not have three failures in 12 months.
"Let's be clear, Usada made a huge mistake by bringing a case against him when their own rules basically state that he had two, not missed tests, but whereabouts violations, as opposed to the three, and they then had to withdraw their case against him," former Olympic 200m and 400m champion Johnson told the BBC Breakfast Show.
"In fairness to Christian Coleman, there is a huge difference between positive tests - or even missing tests - and this situation.
"But if you are going to position yourself as the face of the sport and the superstar of the sport, you have a responsibility to always update your whereabouts and not make the mistake that he did in not updating that those three times and then handling it the way that he did after it came to the public view."