Maria Sharapova "must accept responsibility" for failing a drug test and serve her ban, according to Andy Murray.
The five-time Grand Slam winner, 28, revealed that she tested positive for meldonium in January.
"Clearly if you are taking performance-enhancing drugs and you fail a drugs test, you have to get suspended," said Briton Murray, the world number two.
Russian Sharapova will be provisionally suspended from .
The former world number one says she has been taking the drug, which was added the World Anti-Doping Agency's banned list on , for health reasons for the past 10 years.