Eagle-eyed spectators will no doubt have noticed the strange new club which Phil Mickelson used to great effect during his US Open challenge at Bethpage Black. The hybrid club, which Mickelson helped to design with the assistance of Callaway golf, is actually a prototype club designed to achieve greater consistency and distance from shots out of the rough.

While the club head features a distinctive, rounded sole shape, its centre of gravity means the club handles much more like an iron and features a wedge-style grind and grooves which run up the total face of the 18 degree-club. It has been designed as a rescue club which can be used from a variety of different ball lies as Mickelson showed, using the hybrid club from the heavy, wet rough around the Bethpage course.

The prototype’s grooves conform to the USGA’s new regulations regarding V-grooves, which come into effect in 2010.

Callaway’s head of research and development, Jeff Cotton, revealed that Callaway had spent considerable time with Mickelson at the Riviera Club in Los Angeles, California, and discussed the player’s requirements for the club.

“He wanted his hybrid to play more like an iron, as to where the centre of gravity is placed. And a unique, shallower sole shape allows him to use it out of a variety of different lies in the rough by hitting down and minimising turf interaction.”

However, Callaway have no plans at the moment to release a version of the new hybrid club for club golfers but haven’t ruled out such a release of the club in the future once they have seen how the club performs in the long run.