The advertising executives who came up with the campaign probably figured they had a winner.

	Bo Jackson played with the Raiders from 1987 to 1990 before his career was cut short by a hip injury.

They could not have known just how much of a winner it would be.

It was 1989. Bo Jackson was a big hit, both as a power-hitting outfielder with the Kansas City Royals and as a bruising running back with the Los Angeles Raiders. This was something virtually unheard of. The very thought of playing both sports at the highest level initially had seemed preposterous, but Jackson, a Heisman Trophy winner at Auburn University, was shooting that outdated reasoning to smithereens.

On the evening of July 11, in the All-Star Game at what then was known as Anaheim Stadium, Nike planned to unveil a commercial featuring clips of Jackson playing not only baseball and football but several other sports, each one interspersed with a clip of a player from that sport announcing matter of factly, "Bo knows baseball," "Bo knows football," "Bo knows golf," and so on.

Near the end of the spot, Jackson was depicted trying (and failing miserably) to play hockey, followed by a shot of Wayne Gretzky looking straight into the camera, shaking his head and saying, "No."

The commercial then concluded with Jackson trying to play the guitar, only to be told by legendary bluesman Bo Diddley, "Bo, you don't know diddly."

TWO LEGENDS WHO TRIED

John Elway was a two-sport star at Stanford and had played in the New York Yankees farm system when he was drafted by the Baltimore Colts in 1983 to be their quarterback of the future. Elway, who had no desire to play for Baltimore, used his baseball career as leverage to force a trade to a contending team. The Colts shipped him to the Denver Broncos, and the rest is history. Elway never played baseball again and announced his retirement from the Broncos last month after leading Denver to five Super Bowls, including victories in the past two title games. One of the strangest examples of a two-sport athlete was Michael Jordan, probably the greatest player in NBA history. The guard retired after leading the Chicago Bulls to their third consecutive title in 1993, saying he dreamed of a career in Major League Baseball. The grand experiment took place with the Class AA Birmingham Barons, a Chicago White Sox farm club, and it wasn't long before it was chalked up as a failure. Jordan, whose baseball highlights films usually featured him taking wild swings and catching nothing but air, returned to the Bulls for the 1995-96 season, leading them to three more titles before retiring, again, after last season.

What the advertisers could not have known when the spot was developed was that Jackson would hit a towering home run in the first inning and go on to be chosen Most Valuable Player in a 5-3 American League victory.

It was a watershed moment in the concept of perfect timing, and in the concept of two-sport athletes.

Suddenly, Jackson was an American media icon. Similar spots followed, including one in which, through the miracle of modern technology, several different Bo Jacksons appeared on screen simultaneously in various athletic uniforms. One of the Bo Jacksons, dressed in bicycle tights, earnestly asked, "Hey, where's that Tour de France thing?"

With that, the idea that a single athlete could play Major League Baseball and in the NFL at the same time became acceptable. Not long after, Florida State University's standout defensive back, Deion Sanders, announced he would do the same.

Alas, neither went on to two-sport greatness. Jackson blew out his hip playing in a Raiders playoff game in 1990. He never returned to football after hip replacement surgery but tried to return to baseball with the Chicago White Sox, for whom he still serves as a special instructor during spring training.

But he was never the same.

Sanders has put together a stellar career in the NFL, playing for the Atlanta Falcons, the San Francisco 49ers and the Dallas Cowboys. But his baseball career never really took off after stints with the New York Yankees, Atlanta Braves and Cincinnati Reds, and he eventually gave it up.

The only other man in recent years to try both is outfielder Brian Jordan.

A two-sport star at the University of Richmond, he spent three seasons with the Atlanta Falcons and was chosen as an alternate to the NFC Pro Bowl team as a defensive back in 1992. But baseball was always Jordan's primary sport. That summer, the St. Louis Cardinals got him to agree to a three-year contract with an exclusivity clause, and he hasn't played football again.

Jordan's baseball career took off from there, enough so that when his contract expired last winter, he was one of the more coveted free agents. He spoke of a desire to try the NFL again, but instead, he signed a five-year, $40 million deal with the Atlanta Braves.

Tony Jackson writes for the Denver Rocky Mountain News.