Sports doctors are often asked to compromise their care so athletes can return to their sport, say researchers.
Athletes may not reveal the full extent of injuries
Many of the 18 surveyed admitted they had been pressurised to patch up players to allow them to compete.
Also, management and coaches can demand information about the player's health against patient confidentiality codes, they told the University of Otago team.
The New Zealand researchers questioned whether medical ethical guidelines meet the needs of sports doctors.
They told the Journal of Medical Ethics: "Sports management does not have the same regard for traditional notions of confidentiality, privacy or the patient's long-term welfare."
The doctors surveyed had worked with 22 national and 33 regional or club teams, as well as school sports teams, for more than eight years on average.
Most said they had struggled with ethical dilemmas in their job.
This included disclosing information about whether a patient was using performance enhancing drugs, was infected with hepatitis B or pregnant, for example.
Pressure often comes from the players themselves, the doctors said.
Some athletes want to return to their sport before injuries are fully healed.
Others are unwilling to reveal the full extent of an injury for fear that their coach will be informed and drop them from the team.
One of the doctors surveyed said: "Responsibility to the player, team management and union can present conflict of interests."
John Brewer, head of sports science at the UK's Lilleshall Sports Injury and Human Performance Centre, in Shropshire, said: "Sportsmen and women have always wanted to get back to competing as quickly as possible.
"In the cut-throat world of sport, if you are out of action for some time then it can be difficult to get back in.
"The medical profession have a responsibility to look after the well-being of the athletes they are working with. One would hope that they have that duty of care."
But he agreed that sports doctors were sometimes put under pressure.
He said it was vital to have a coherent team making decisions, comprising the athlete and their doctor, coach and physiotherapist, for example, rather than putting all of the pressure on one member.
"There are far too many instances of sports people who have gone back too quickly and suffered a more serious problem as a result of not having full rehabilitation," he said.