Australia's Jordan Thompson called the ban handed to his US Open-winning doubles partner Max Purcell a "joke", questioning what he said was a lack of consistency in punishments for doping violations.
Purcell elected to take a provisional suspension under the International Tennis Integrity Agency's Tennis Anti-Doping Programme, saying he had unknowingly received an IV infusion of vitamins above the allowed limit of 100 millilitres.
The ban will keep the twice Grand Slam winner out of next month's Australian Open, where he was to join forces with Thompson four months on from their triumph at Flushing Meadows.
"I don't think he's quite happy and neither am I to be honest," Thompson told Australian media.
"He took too much in an IV bag – to get suspended for that when there are other people who have done far worse and sometimes just get a slap on the wrist, it's a bit of a joke I think.
"But it's not up to me to decide what happens. When you look at guys testing positive and then you have Max taking just too much in an IV bag, it's a head scratcher."
Purcell is the latest Grand Slam winner to be investigated by the agency, which was established to safeguard the sport's integrity by the game's governing bodies.
Last month French Open champion Iga Swiatek accepted a one-month suspension after testing positive for the banned substance trimetazidine following contamination of her sleep medication.
Jannik Sinner, the world No 1, was cleared of wrongdoing after failing two tests in March for anabolic agent clostebol but faces a possible two-year ban after an appeal by Wada, the global anti-doping body.
Both players have been cleared to play at the Australian Open, which starts on January 12.
Purcell's suspension means the 27-year-old, who also won the men's doubles title at Wimbledon in 2022, cannot play in or attend any event authorised by tennis' governing body, leaving Thompson looking for a new partner.
"It wasn't great news for me and Maxy – especially Max," Thompson said. "I think it's a bit of a joke, but there's not a lot I can do about it."