It's called a high ankle sprain, which means the ligament joining the two bones of the lower leg – the tibia and the fibula – is stretched or partially torn.
Fixing it sometimes requires surgical carpentry (inserting one or more screws to hold the sinewy tissue together) and generally a lengthy rest.
So why is it that the New England Patriots' medical staff is leaving it up to tight end Rob Gronkowski to decide whether he wants to play in Sunday's Super Bowl barely two weeks after suffering the injury?
The question contains its own answer. As one orthopedic surgeon, who has experience treating professional football players, told The Globe and Mail: "If this were your child or mine, I'd say 'here's your cast, see you in four weeks.' But that's not how it works in the week before the Super Bowl."
As the NFL prepares to stage the most-hyped annual event in pro sports, another story is burbling in the background, one that doesn't quite fit with the narrative of celebration.
The world's most profitable sports league is being sued by 300 former players, many of whom, such as former Dallas Cowboys star Tony Dorsett, allege that the league and its doctors "used" them and willingly exposed them to serious injury.
To be fair, sprains aren't usually career threatening, and Gronkowski told reporters in Indianapolis this week that as long as he can stand the pain in his left leg, he'll play in the big game.
"I will make the final call," he said. "I listen to the trainer's advice, but it's how I feel. I'm just trying to get better."
While the tight end's toughness is of a piece with football's hard-man tradition, it's also clear the Pats stand to benefit from his presence in their offence. Yet it's also a truism that players are more than willing to play hurt during regular-season games. That's where his situation, like countless others, slides into murky ethical territory.
Physicians employed by professional sports teams face competing pressures, said Arthur Schafer, director of the Centre for Professional and Applied Ethics at the University of Manitoba.
The Hippocratic Oath states their first consideration is the life and health of the patient. Yet they are often working for corporations with obligations to shareholders; it is common practice for NFL teams to create bidding wars between clinics and hospitals who are willing to pay for the (highly profitable) distinction of being a team's official medical provider.
"It is not they aren't concerned, but they are balancing the concern for long-term health considerations, the bottom line, with corporate concerns with shareholder's best interests," Schafer said of team doctors. "In general, what is prudent for the players, what is in their best interests, will sometimes, perhaps often, coincide with what is best for the team's owners."
But there will be points where those interests diverge.
"At that point, the physicians [teams]employ, either full-time or as consultants, are going to feel competing pressures," Schafer said. "They are going to be in a conflict of interest. Their fundamental professional duty is to the life and the health of their patient, where their marketplace self-interest may well be to please management."
Former offensive lineman Greg Lotysz, whose NFL hopes were dashed by a training-camp knee injury, would tell you he's a living illustration of those conflicting priorities.
"Initially when you get hurt, you have no choice," Lotysz said. "You get hurt on the field and they have the first doctor to check you out. But if they are employed by the team, whose best interests do they have in mind? The person who comes to them in good faith and says help me?"
Just a decade ago, Lotysz thought he had it made.
The 6-foot-6, 310-pound Thunder Bay native was signed as an offensive lineman by the New York Jets and, in July of 2000, he was told he'd be playing in the preseason. But a knee injury during practice sent him to surgery, where he caught two infections.
At one point, Lotysz was told he might lose his left leg. Instead, he lost his football career and his ability to walk and live normally. He sued two of the Jets' doctors for malpractice. The case went to a New York appeals court where it was shot down by a state law that prohibits employees from suing one another over a workplace injury.
The doctors were considered employees of the Jets and not independent contractors.
"When we asked for the contracts between the Jets and the doctors, they said, 'They're oral contracts,'" said Lotysz, who is on NFL disability benefits and still can't work because of the pain he experiences. "Look at [the doctors']pay stubs. They're getting $15,000 a year. They also get advertising [from being associated with an NFL team] They get executive boxes for family members. They're well covered."
What Lotysz learned was how the system works in pro sports – the more stature a player has, the better he'll be taken care of.
"That second, third, fourth medical opinion, that comes with the level of your position in the game," said Lotysz, a father of three who has since earned a master's degree in sports psychology. "Me, I'm an offensive lineman. I'm on the practice roster. You're worried about getting cut, your future, the money you're making. When they tell you there's nothing wrong, go to rehab, you do what you're told. It's not until your fourth surgery and you've lost 70 pounds that you say, 'I don't care. I'm fighting this.'"
With reports from Robert MacLeod and The Canadian Press