Callaway has asked the USGA to remove the Tour i ball with a sidestamp from its list of   conforming golf balls because some may exceed the USGA's weight limit.

In a release on the company's Web site, Callaway explains, "The deviation in ball weight was traced to a manufacturing anomaly that occurred on two days in mid-2008."  Callaway went on to say that less than 1% of Tour i balls were affected. Theoretically, the heavier balls could fly farther on well-struck shots.

Going forward, Tour i balls will be marked with a sidestamp that has two dots on either side, like this one: . 

The only golfers this will truly affect are professionals and elite amateurs. Starting in June, those golfers will need to use the ball with the two-dot sidestamp. All other golfers may continue to use the former version of the Tour i ball, even for rounds that are counted toward handicap calculations.