No one can play forever, but these guys didn't even stick around for as long as they could have.
Earlier today, Tony Romo made it official. He announced he was retiring from the NFL to begin a broadcasting career at CBS. This move came as a shock to many. It was widely expected that Romo's days with the Dallas Cowboys were done, but it was also anticipated that he'd find his way onto a contending roster (in Houston, or Denver, perhaps) via a trade or free agency if he was released.
Romo will turn 37 later this month, but several people aren't convinced he's really done playing. We'll have to wait and see however.
While the Romo news was unexpected, it is hardly unprecedented. There have been several athletes who left their respective fields while still in the prime of their career. Romo isn't even the best, or youngest, to do so.
Without further ado, here are five athletes who surprised the sports world by stepping away with a lot left in the tank.
Jim Brown - Cleveland Browns, RB
There are some who still think Brown is the greatest running back of all-time and perhaps the best all-around player, period. In nine seasons with the Cleveland Browns, he eclipsed the 1,000-yard mark seven times and scored 17 touchdowns in 1965, his final season.
The eight-team All-Pro runner retired in July 1966, just five months after turning 30, and embarked on a successful acting career. He still ranks fifth in all-time rushing touchdowns and 10th in total touchdowns.
Imagine what would have happened if he had stayed for a couple of more years.
Tiki Barber - New York Giants, RB
Barber announced in October 2006 that he would be retiring at the end of the season. The timing was odd: after all, it was mid-season, and he was on his way to rushing for 1,662 yards.
Barber was 31 when he hung up his cleats, which is almost ancient in running back years. However, because he wasn't used extensively his first three seasons in the NFL, he wasn't as worn out as runners his age typically are.
Barber saved his best three seasons for last, and then stepped away to get into television. The Giants went on to win Super Bowl XLII in their first season without him. Ouch.
Barry Sanders - Detroit Lions, RB
Are you sensing a pattern here with running backs? Sanders stunned the football world when he announced he was quitting in July, shortly after turning 31.
In 1997, his second-to-last season, Sanders topped 2,000 yards and rushed for 11 touchdowns. For his career, he rushed for 15,269 yards and 99 touchdowns in 10 seasons.
The highlight reels were made for this dude.
Michael Jordan - Chicago Bulls, SG
You knew this one had to be on here. In 1993, fresh off a three-peat with the Bulls and an NBA Finals in which he averaged a record 41.0 ppg, Jordan shocked everyone when he announced he was retiring and trying his hand at baseball.
Of course, we all know how this ended. Jordan's time on the diamond did not last long, and he returned to the court in March 1995. He led the Bulls to another three-peat from 1996 to 1998, retired for a second time, came back with the Washington Wizards and finally hung it up for good in 2003.
When it came to premature retirements, Brett Favre had nothing on Air Jordan.
Magic Johnson - Los Angeles Lakers, PG
Of all the announcements on this list, none shook up up sports fans, and the public in general as much as Magic's did on November 7, 1991. That was the day the 32-year-old superstar told the world he had contracted HIV.
Despite his diagnosis, Magic played in the 1992 NBA All-Star Game and with the Dream Team at the Barcelona Olympics. He even made a return to the NBA in 1996, and despite being 36 years old and considerably heavier than he was during his earlier stint with the Lakers, Magic averaged 14.6 points, 6.9 assists and 5.7 rebounds in 32 games.
These days, Magic is the Lakers' new President of Basketball Operations, and he's focused on returning his old team to glory.
What do you think about our list? Anyone we missed?