The USGA Makes It Official...

...a U-groove ban has been proposed.

The key lines from the press release:

The proposal calls for two key additional groove specifications for clubs. One would call for groove edge sharpness to be limited to an effective minimum radius of .010 inches. The second would limit the total cross-sectional area of a groove divided by the groove pitch (width plus separation) to 0.0025 square inches per inch.

The changes in grooves required under the USGA’s proposal would have very little effect on the performance of Surlyn balls favored by most golfers.  More than two-thirds of golf balls sold in the U.S. are Surlyn covered.  The impact of this proposal would be felt primarily by highly skilled players using urethane-covered balls.  

The USGA proposes that these new groove rules become effective for all new clubs covered by this rule change that are manufactured after Jan. 1, 2010. A related Condition of Competition would be added to the USGA Rules of Golf to become effective Jan. 1, 2009. This Condition would allow a Committee to require the use of clubs that conform to the new groove rules for competitive events conducted after Jan. 1, 2009.  Similar to other equipment-related Conditions of Competition, the USGA would recommend that the Condition apply only to competitions involving highly skilled players.