Is groin injury first sign of LeBron James aging?

The ball in his hands driving toward the basket, LeBron James is one of the most feared men in the NBA.

But not on Christmas Day, with Draymond Green in his way, James awkwardly lost his dribble and fell to the floor. James came up grimacing after the play and has missed Los Angeles' past four games because of a groin strain, with his status for Sunday's game vs. the Timberwolves to be determined.

It's a rare sight to see James sidelined, with him having played in 94 percent of possible games in his career. He has never missed a playoff game.

James has been the epitome of health and has performed at a superstar level throughout his 16-year career. His rookie year statistics mark the worst averages of his career for points (20.9), assists (5.9), rebounds (5.5), field goal percentage (41.7) and three-point field goal percentage (29.0).

But even as James continues at a torrid pace — he's averaging 27.3 points, 7.1 rebounds and 8.3 assists per game while shooting 51.8 percent from the floor and 36 percent from three-point land in his first year with the Lakers — he's facing an undefeated foe: Father Time.

Having just turned 34 on Sunday and with this groin injury, it's a reminder that the bill is closer to being due.

"I don't know," James said when asked in a recent ESPN interview about age catching up with him. "I've always taken care of my body. I've always worked 24/7 nonstop. ... I never put a ceiling, or never said how many years I wanna play."

For a better estimate of that, let's assess some other players of his caliber and skill who went made the jump from high school to the pros and when their skill-sets started to show regression with age.

• Tracy McGrady entered the NBA in 1997 and was a seven-time All-Star and seven-time All-NBA honoree who was inducted into the Basketball Hall of Fame in 2017 after a 15-year career. But after his age 28 season he never averaged more than 15.6 points per game and only once played in 52 or more games in a season.

• Kobe Bryant entered the NBA in 1996 twice led the NBA in points per game, was an 18-time All-Star and one-time NBA MVP who received 28 All-NBA honors during his 20-year career. After his age-34 season, he played three more seasons but only once played in 66 or more games or averaged 17.6 points or more per game.

• While not a wing like James, Kevin Garnett provides another high-school-to-pros case study. After his age 30 season he only once averaged more than 15.8 points per game. The longtime double-double machine also never again averaged double-digit rebounds after his age-30 season.

• And no James comparison story is complete without Michael Jordan, who averaged less than 26.9 points per game only three times in his career and two of those seasons were after he turned 38 and had come out of retirement for the second time.

His predecessors' earlier declines suggest that James might be playing on borrowed time. But then again, the continued evolution of sports science and body-mind mastery just might keep him ahead of the curve.

James' business partner, Maverick Carter, told the Ringer in June 2016 that James spends about $1.5 million annually to keep his body running like a well-oiled machine.