Discovering the contents of Phil Mickelson’s bag at the beginning of a Major week always makes for interesting reading. 

For equipment junkies he is the gift that keeps on giving; be it two drivers, as he famously carried at the 2006 Masters, en route to a two-shot victory and second Green Jacket. 

Or the no-driver strategy at Torrey Pines for the first two days of the 2008 US Open. The plan backfired and, come the weekend, the driver was back in the bag.

At Muirfield last year Mickelson again employed a plan which didn’t include a driver, instead opting for a 3 wood which was long enough to be used off the tee as well as from the deck. 

Callaway’s technicians put together an X Hot 3Deep with a face that was 10 per cent taller than the usual X Hot which made it more in line with the impact area on tee shots.

At the par-5 17th hole in the final round, where nobody had got close to threatening the green, the Californian whistled a second 3 wood over 300 yards to the putting surface.

“That was the moment that I had to kind of compose myself, because I hit two of the best 3 woods I’ve ever hit. That is exactly why I don’t have a driver in the bag. Those two 3 woods were the two best shots of the week.”

In December last year I was lucky enough to visit Callaway’s headqaurters in Carlsbad, California where two afternoons were spent at the Ely Callaway Performance Centre. 

This is where the Open champion spends much of his time tinkering with his bag, he lives just 25 minutes away, and working with Austie Rollinson, the principal designer for Odyssey Golf and Randy Peterson, Callaway’s director of fitting and instruction.

In the corner of one room sits a bag with Phil’s back-up equipment and cast offs, clubs that have won tournaments and some that might never see the light of day.

Both experts in their field have worked with the left-hander since he joined the company in 2004, a period which has seen him capture four of his five Majors. And both know Mickelson better than pretty much anyone in the game. 
He is not afraid to fail and when he has a chance to win he gets more aggressive" The putter changes 

AR: One phone call that was surprising was when he asked me to make him up a belly putter the same specifications as Keegan Bradley.

He has a good sense of equipment, he has greens in his back yard with different speeds and slopes. He will practise 20 to 30 minutes at a time and then his mind starts to wander.
People think he’s very specific with grips but sometimes he’ll just pick one up and give it a go.

The swap to Versa No 9

AR: In October 2012 he got the Versa No.9. He texted me before Hawaii and we sent all our pros a gift box with the Versa No 1 and he was trying it at home. 

He said it was like a Zen thing where he knew where the face was so he wanted me to make up a No 9 for him; he used it at Humana and then he went away from it at the Waste Management where he used an old Black Series putter with an aggressive milled mark on the face which he used at Sandwich when he nearly won the Open. 

So I texted him and asked if I could make him up a No 9 with an added sight line that was on the Black Series version, and a new SuperStroke ‘Slim 55’ grip and he hasn’t changed it since.

His putting stroke

AR: We have a replica putter from the Open Championship here and he has almost half an inch of offset; he has done that as he used to forward press a lot and he would deloft it. Some of his putters were 5 or 6˚ and now it is 4˚ but that gets his hands in the right position.
He found something in his stroke in 2013, he hasn’t told me what it was, but it might be how he brings the putter back.

His club testing

RP: Roger Cleveland does the wedges and I look after the irons, fairways and driver. The weird thing with Phil initially, and he still does it to some extent, is that he would hit club for club on the range and he would look at the flight and then try to achieve a flight that he wanted. 

So if it was drawing it too much he would want the club flattened. 

I would keep a note of all the changes and there would be no progression to his set. He might end up with a 2 iron, which was flatter than his 4 and more upright than the 7. They were all over the place. It was just done on flight and he is still a bit like that.

We work more on the design on what he wants in a club, like the depth and where he wants the centre of gravity in a wood. 

The driver policies

RP: He is unique as he is never really satisfied. He could be hitting it perfectly but will never settle. He is very self-effacing and will easily say that the two drivers at Augusta might have worked but the no-driver at Torrey Pines didn’t work. 

We were confident about the two drivers as the week before he won by 13 shots. He hasn’t done it since which shows how he keeps trying to do things differently.

Two years ago when he won at Pebble playing with Tiger he shot a 64 to Tiger’s 75 with the Razr Fit driver and he hit 13 or 14 fairways. 

On the Monday he gave me the driver and said he didn’t want it any more as he didn’t think it was set up to go as far as it could.

At Hoylake he might have a 1 or 2 iron. Before the Open he will go to The Farms in Santa Fe as it has the tightest fairways around.

The man

RP: He is not afraid to fail and when he has a chance to win he gets more aggressive. I think in some circumstances he just gets bored and tries different stuff to keep it fresh and exciting. 

We play golf together, go to lunch together and I have never seen him treat anyone differently. He doesn’t have a different side. 

He knows everyone’s name, is very appreciative of people’s time and expertise and is never condescending. He’s a genuine guy.