History of Joel Embiid's injury

Because they are so infrequent, injuries to the navicular bone aren't dreaded the same way as ACL and Achilles injuries, or microfracture knee surgery. But for a big man, there's no worse sentence than the one Joel Embiid received Thursday: a stress fracture to the navicular bone in his right foot, for which he'll undergo surgery immediately.

Recurring navicular injuries ended Yao Ming's career prematurely, and kept Bill Walton on the sidelines for much of his prime years. Now, teams considering drafting Embiid must weigh his potential against the possibility that he suffers a similar fate.

Past precedent

My research turned up four big men who have suffered navicular injuries in addition to Walton and Yao: Curtis Borchardt, Brendan Haywood, Zydrunas Ilgauskas and Kevin McHale. There have also been a handful of perimeter players with navicular fractures, including Michael Jordan, during his second season, and Philadelphia 76ers guard Andrew Toney, who missed nearly the entire 1985-86 campaign and was never the same again.

Despite Toney's example, navicular injuries have been more problematic for big men because of the additional weight and pressure they put on their feet. Discounting Hayward, who missed all of last season after undergoing surgery in October for a stress fracture of his navicular, the other five post players missed an average of 47.5 percent of their teams' scheduled games in seasons after the injury.

Taking each player case-by-case reveals the wide range of possible outcomes for Embiid.

Curtis Borchardt (played 83 of a possible 328 games)

Like Embiid, Borchardt first experienced problems with his navicular bone before entering the NBA. He missed portions of his freshman and sophomore seasons with stress fractures, undergoing surgery the second time and returning for a healthy junior season when he averaged 16.9 points and 11.4 rebounds per game. On the strength of that performance, the Utah Jazz traded up to draft Borchardt 18th overall in 2002.

With the Jazz, Borchardt suffered a recurrence that wiped out his entire rookie season and he missed much of his second season due to a fractured wrist before playing 67 games in his only full campaign, the 2004-05 season. Borchardt was subsequently traded to the Boston Celtics, and his NBA career was finished when the Celtics waived him during training camp, though he was able to play overseas through 2012.

Zydrunas Ilgauskas (played 756 of a possible 902 games)

Ilgauskas offers perhaps the most hopeful outcome for Embiid. Ilgauskas' navicular injury -- which kept him from playing during 1996-97, his rookie season -- was again suffered five games into the 1998-99 season, limited him to 29 games over the next three seasons.

But remarkably, after returning to the court in December 2001, Ilgauskas played at least 78 games each of the following five seasons, moving past his foot issues to become a two-time All-Star. He remained a contributor through his retirement in 2011 at age 36.

Kevin McHale (played 419 of a possible 492 games)

A broken navicular bone was the injury McHale famously played through during the 1987 playoffs, helping the Boston Celtics get to the NBA Finals before losing to the L.A. Lakers. McHale underwent surgery over the summer, which cost him the first month of the 1987-88 season. Thereafter, he played in 64 of 68 games, and missed just four total over the following two seasons. He made the All-Star team four times after the navicular injury before slowing down and retiring at 35.

Bill Walton (played 259 of a possible 738 games)

While playing through pain in the 1978 playoffs, Walton fractured his navicular bone in Game 2 of the Portland Trail Blazers' series with the Seattle SuperSonics -- the last he'd play for the Blazers. After sitting out the entire 1978-79 season, Walton signed with the San Diego Clippers, for whom he'd play just 169 games over six years, missing all of 1980-81 and 1981-82.

Following surgery to reshape his arch, Walton was eventually able to contribute to the 1986 champion Celtics and win the NBA Sixth Man Award. That would prove his last hurrah, as Walton played just 10 games during the following season, his last in the NBA, before being diagnosed with another navicular fracture -- one that, ironically, prompted McHale to play through the same injury.

Yao Ming (played 82 of a possible 246 games)

At 7-foot-6, Yao had already dealt with foot and knee trouble, including a fractured fifth metatarsal bone in his foot, when he was diagnosed with a stress fracture of his navicular bone in February 2008. The Houston Rockets hoped at the time that they'd caught the injury early enough to prevent it from becoming a problem, and Yao returned from surgery to play in the Beijing Olympics and 77 games in 2008-09, when they won their first playoff series since 1997.

During the conference semifinals against the Lakers, however, Yao reinjured the navicular bone. He underwent reconstructive surgery and was ruled out for the entire 2009-10 season before attempting to return the following season. Another stress fracture to his ankle suffered after five games led to Yao's retirement at age 30.

Embiid impact

When considering the impact of Embiid's navicular injury on his draft stock, the severity is hard to overstate. Not only could it potentially keep him off the floor all of next season, the chance of recurrence will always linger. There's a hope that, like Ilgauskas, he could eventually enjoy a long and productive career. But teams picking at the top of the draft must also be prepared for the possibility that Embiid misses multiple seasons or even has his career cut short.