Here's a cool proposal. Some San Mateo geeks are developing a sports player stock market, so you can buy and sell athletes as if they were equities.

Sports fans may soon be wondering whether their "shares'' in 49ers quarterback Tim Rattay are falling or whether they should add Raiders wide receiver Randy Moss to their portfolio.

That's because a San Mateo startup called Protrade Inc.... plans to launch an online venture that assigns a value to pro athletes as though they were publicly traded companies."It's much more similar to a sports stock market than a fantasy sports league,'' said Protrade co-founder Mike Kerns....

...Fantasy sports are now a major hobby for an estimated 32 million people whose average household income is about $89,000. Fantasy sports leagues typically use a scoring system based on the statistics of players in sports such as football, baseball and basketball.

But Kerns and Ma have developed a more intricate system to determine a pro athlete's value based on performance during different game situations and contribution to a team's wins or losses. The analysis also takes into account factors that could affect performance, such as trade rumors, injuries, contract holdouts, coaching changes and arrests for crimes.

Protrade members can then watch the value of players in their portfolio rise or fall, deciding, like a day trader, whether to buy low or sell high.

Scouts and player personnel managers at pro sports franchises beware. The market is going to vote on your judgments.