In one legendary example of an athlete's playing through sickness, Michael Jordan dribbled his heart out in a 1997 Chicago Bulls playoff game against the Utah Jazz, despite flu-like symptoms that left him nauseous and so weak he could barely stand. He scored 38 points, getting fluids and air between quarters.
Doctors said it won't hurt a normally healthy athlete to play through sickness. If anything, it will temporarily weaken the immune system and slow down recovery, Tucker said.
"The bigger risk is if they are exposing everyone else around them," said Aaron Milstone, an assistant professor of pediatrics and an epidemiologist at Johns Hopkins.
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Tucker said players are sent home if they are contagious, a state that can last as long as a week. Generally, flu patients are not contagious 24 hours after their fever breaks, Milstone said.
Doctors look at players' symptoms on a case-by-case basis, Tucker said. People with symptoms from the neck up, such as congestion and runny nose, or not as bad off as those with symptoms in the lower part of the body, such as aches and pains.
Players don't always like doctors' orders, particularly during playoff season, but it's protecting the team, Tucker said.
"We will have them stay home even though practice time and meeting time is important to them and their coaches," he said, "because the greater good sometimes is to keep them home until they're deemed safe to be around their teammates."
Baltimore Sun reporter Aaron Wilson contributed to this article.