But while such injections remain a widely accepted treatment for elbow and shoulder injuries, those administered anywhere near the Achilles tendon are far less common, far more problematic.
Ample medical evidence suggests cortisone can damage surrounding tissue, fray the Achilles, even trigger a rupture. According to one recent survey of orthopedic physicians - many of whom unhesitatingly prescribe cortisone for tennis elbow or rotator-cuff problems - two-thirds would not use it to treat an Achilles injury.
Did cortisone contribute to or hasten Howard's tear? Would it have been wiser in the long run for him to forgo the shot, even if it meant missing the postseason? Was the decision his alone? Did the Phillies recommend and endorse the treatment? If so, why would the team take such a risk with a franchise player to whom it owes $125 million?
"There wouldn't be any way that you would back me into the corner on anybody [with an Achilles problem] to go ahead and inject them," said Dr. Michael Schafer, an orthopedic consultant to the Chicago Cubs and chairman of the orthopedic surgery department at Northwestern University Hospital. "I've been in practice since 1974 and been involved in sports all my life. When it comes to the risk of an Achilles tendon tear, I'm concerned about cortisone."
Because the drug masks pain instead of addressing its root cause, some fear it encourages patients to overuse the significant weight-bearing tendon, risking additional damage. Dr. Karim Khan, a researcher and professor at the University of British Columbia, told the New York Times in 2010 that cortisone injections may actually "impede the structural healing."
On Oct. 7, of course, less than three weeks after receiving the shot, Howard completely tore his left Achilles on the final, frustrating play of the Phillies' 2011 season.
His dramatic breakdown raises questions about the drug and the late-season injection, questions that resonate more loudly now as the punchless Phils, still without their recuperating cleanup hitter, have stumbled early in 2012.
Not for discussion
Answers are difficult to come by. When The Inquirer requested an interview on the subject with team physician Michael Ciccotti, a Phillies representative replied in an e-mail that the club preferred to "pass on participation for this story."
Howard, meanwhile, remains off-limits during his rehabilitation in Clearwater, where, again according to the team, he is unavailable for comment. His agent, Casey Close, also preferred not to comment.
Even if they were willing to discuss details of the injury, their answers almost certainly wouldn't absolve or implicate the cortisone injection.
It's possible Howard's stressed left Achilles - the tendon that connects the heel to the muscles of the lower leg - would have burst even without the cortisone injection. The 6-foot-4, 230-pound first baseman, after all, had been having foot problems for more than a year after badly spraining his left ankle in August 2010.
Achilles ruptures happen. Eagles lineman Jason Peters tore his Achilles in a workout in March. Peters and the Eagles would not discuss his injury.
But interviews with physicians and an examination of research on the subject make it apparent that, if nothing else, the Phillies and Howard took a sizable gamble Sept. 18.
Two days prior to getting the shot, Howard indicated he was considering one. "We'll discuss it," he said, "and see if that's the best option."
Apparently, he was aware of the risks. On his February arrival at the Phils' spring-training site, four months after the tendon had been surgically repaired, he indicated to reporters that he felt it was possible the drug had played a role.
"I don't know if cortisone leaked in there or not or whatever," he said.
The drug's potentially negative side effects are as well-known as its benefits. Among those listed on the Mayo Clinic's website are "skin and soft tissue thinning around injection site" and "tendon weakening or rupture."
The website of Jefferson University Hospital's Rothman Institute, where the Phils' Ciccotti is listed as director of sports medicine, notes that "studies have shown an increased incidence of Achilles tendon rupture after cortisone injections."
To be fair, the greatest danger lies with injections directly into tendons, a practice that has become medically taboo. But many doctors believe the heel's compact anatomy and cortisone's degenerative possibilities make injections like Howard's, those very near the vulnerable Achilles, risky.
"Even when performed carefully," wrote Jonathan Cluett, an orthopedic surgeon in Massachusetts, "injections of cortisone around the Achilles can lead to traumatic rupture of the tendon."
Howard might be a big man, but the retrocalcaneal bursa, where he was injected, is tiny, its surface perhaps no bigger than a nickel. The sac is so small that, according to Schafer, it's not unusual for cortisone to wind up elsewhere.
"In the shoulder, there's a huge sac," said Schafer, who is also on the board of the American Academy of Orthopedic Surgeons. "You've got a big injection area. In the Achilles you don't."
Since neither Howard nor the Phillies are discussing the procedure, no one else knows for sure whether imaging devices like X-rays or ultrasound were employed to help the physician pinpoint the bursa.
Not all orthopedists share Schafer's reluctance about cortisone injections in the heel.
"It really depends on your comfort level" said Dr. Rob Raines, an orthopedic specialist with the Cincinnati Reds. "It certainly can be done safely. I'm comfortable [with the procedure] and commonly do inject the Achilles bursa. That's likely because I'm a foot and ankle orthopedic surgeon and feel very comfortable with the anatomy around the Achilles tendon."
Despite the evidence linking cortisone and Achilles damage, there's far from agreement on the topic. Much of the uncertainty can be attributed to the fact that most of the research has been done on animals.
"No one is going to do a study where you're injecting in there," said Dr. Gary Green, Major League Baseball's medical adviser. "You'd be risking an Achilles rupture."
Whatever its perils, cortisone continues to be among the most popular therapeutic drugs in sports medicine. Several years ago in a lawsuit filed against the Miami Dolphins by former Penn State receiver O.J. McDuffie, the NFL team's physician testified to its "tremendous use and misuse" in football.
It's just as common in baseball; the Phils are hardly the first team to treat a superstar's painful heel with cortisone.
In 1996, even though the San Diego Padres' medical staff initially balked at injecting the drug so close to his Achilles, Tony Gwynn had at least one cortisone shot near the tendon. A year later, Cincinnati's Barry Larkin had two injections.
Both players ended those seasons with a partially torn Achilles.
In this cloudy atmosphere, players like Howard and teams like the Phillies continue to take chances. In fact, for those athletes willing to sacrifice virtually anything to prolong their careers, cortisone is often seen as a godsend.
Asked if he'd been aware of the link between cortisone and Achilles tendons before his injections, Larkin said he had not been.
"It didn't matter. I just wanted to play," Larkin said. "I would have done anything if it kept me out on the field."
Larkin, who will be inducted into the Hall of Fame this summer, played another seven years after his Achilles tear - one that was far less severe than Howard's. His assessment of his performance in that span should be sobering for Phillies fans.
After being named the NL's MVP in 1995 and a 33-homer, 36-stolen-base performance in '96, Larkin's production dropped off dramatically.
"I was never able to hit the ball with such authority again," he said. "I felt like my power was gone. Defensively, I felt I had to cheat because I could no longer go to my right the way I had."
Year of pain
Howard's Sept. 18 injection came after more than a year of discomfort. On Aug. 1, 2010, as he lunged awkwardly back to second base at Nationals Park in Washington on a failed pickoff attempt, he severely sprained his left ankle.
He returned from the disabled list Aug. 21, but early in the 2011 season, the first baseman's foot woes flared. They were exacerbated July 20 when he and the Mets' Jason Bay collided at first base. Howard sat out July 24 and over the next three weeks would miss nine more games.
When the pain persisted through mid-August, the Phillies revealed that he was suffering from bursitis in the left heel near the Achilles. Finally, on Sept. 16, manager Charlie Manuel conceded that for Howard's foot to get completely well, "it's going to take the offseason."
A day later, when the first baseman was benched again, general manager Ruben Amaro told reporters a cortisone shot had been prescribed. "The doctor is going to inject him in the bursa sac," Amaro said. "We've got to calm it down."
Howard rested for nearly a week after the shot, returning to the lineup Sept. 24. That layoff highlighted another area of uncertainty about cortisone use: No one knows precisely how long a postinjection rest ought to be.
"We know we've weakened your tendon for a period of time," said Schafer. "But if I inject you today, no one can say when the Achilles tendon is at its weakest."
The game after his return, complaining of a sore left ankle, Howard had to leave after four innings. "I'm not going to try to play the hero with six games left," he said.
But, some would argue, that's exactly what he'd done a week earlier by submitting to the risky injection.
Unlike the International Olympic Committee, which bans oral corticosteroids and requires an exemption for their injection, baseball does not restrict use of the drug.
According to Green, Major League Baseball's medical adviser, in treating players, team physicians are free to use any drug not on the sport's banned list.
"Ultimately, they are liable for the decisions they make," Green said.
Contact Frank Fitzpatrick at 215-854-5068, firstname.lastname@example.org, or @philafitz on Twitter. Read his blog, Giving 'Em Fitz, at www.philly.com/fitz.