Major League Baseball players have ended decades of opposition to mandatory drug testing by agreeing to be checked for illegal steroids starting next season.

Under the proposal, made by the players union on Wednesday, players would be subjected to one or more unannounced tests in 2003 to determine the level of steroid use.

If the survey shows "insignificant use," a second round of tests would be set up in 2004 to verify the results. If more than five percent of the tests are positive in either survey, players would be randomly tested for two years. The players union did not say what penalties, if any, would be levied against those who test positive for steroids.

It is unclear how management will respond to the proposal. Baseball owners earlier this year had put forth a plan calling for more extensive testing.

Drug testing has long been considered a key issue in contract talks between players and owners.

Earlier this year, former baseball stars Jose Canseco and Ken Caminiti admitted to steroid use, with Canseco claiming that up to 85-percent of all major leaguers took some form of muscle-enhancing drugs from 1985 to 2001.