Lance Armstrong was in danger of losing the Tour de France last month because he wore the wrong color jersey.

Before Stage 4 of the 2,200-mile bike race around France, Armstrong wore his team's blue and white jersey. But a tour official told Armstrong he could be disqualified if he didn't wear le maillot jaune -- the yellow jersey -- worn by the rider who has the overall lead in the race.

Armstrong said he didn't think he should have the honor of wearing the yellow jersey because he was in first place only because another cyclist had fallen. If not for the crash, the other cyclist, not Armstrong, would be the overall leader.

The race official disagreed and told Armstrong to wear yellow -- or else. (Armstrong wore the yellow jersey for most of the rest of the race, winning his seventh straight tour.)

Color is very important in sports. Color tells fans who the home team is. It keeps athletes cooler under a beating sun. It even helps competitors, who speak different languages, communicate. It oozes meaning.

The yellow jersey appeared in the early 1900s after Tour de France spectators complained they couldn't spot the leader among dozens of cyclists. Soon, the functional "you're it" had become a badge of honor.

Like the yellow jersey, the idea behind the green jacket of the Masters golf tournament was to stand out in a crowd.

The tradition began in 1937 when members of the Augusta National Golf Club wore green jackets so visitors could identify "a reliable source of information," according to the Professional Golfers' Association.

Masters champs began getting green jackets in 1949, starting with Sam Snead. Winners have slipped on a green jacket ever since.

The rules say the winner is allowed to take home the jacket for one year, but has to return it when he defends the title the next year. This year Tiger Woods won the Masters and wore his jacket a fourth time.

Green symbolizes achievement in golf, but some colors aren't so positive. Whether an 8-year-old striker or a 30-year-old sweeper, no soccer player wants to see red.

At the 1970 World Cup tournament, referee Ken Aston popularized a two-color card system. A yellow card was a warning for a rule breaker, and a red card meant the player was ejected from the match. Today the cards are used in all levels of soccer competition.

Why did Aston invent the color-coded cards? Because opponents, sometimes even referees, spoke different languages. If a player did not understand, or chose not to understand, that he had been sent off, there was no question.

Color made it clear.

-- Bill Webster

Phil Mickelson helps Masters winner Tiger Woods put on a green jacket.At the Tour de France, Lance Armstrong always seems to be sporting a yellow jersey, worn by the overall leader.A red card is bad news for soccer players.