Andy Murray says Viktor Troicki and Marin Cilic were “unprofessional” and have no excuses for the doping offences which led to their suspensions.
Troicki had an 18-month ban reduced to 12 months this week for skipping a blood test in April, though he provided a urine sample which proved negative. Cilic served a four-month ban after testing positive for a banned stimulant in May, but claimed he had not intended to ingest it in a glucose tablet bought at a pharmacy.
Speaking to the BBC, Murray said there "almost has to be zero tolerance" for tennis to stay credible in the public opinion.
The Wimbledon champion added: "Whether either player was intentionally cheating or not — we don't know that, and I don't think either of them are like that —but both of them were unprofessional."
"I personally would never go and buy something over the counter in a pharmacy. It's just unprofessional."