On the eve of last year's Masters, the club announced plans to strengthen the par-4s to 'keep the golf course current with the times.' Two days later, Johnson was headed toward Amen Corner when he noticed a ball rolling down the 11th fairway.
It was Phil Mickelson's tee shot, and it was long enough to make Johnson curious.
Dressed in his green jacket, the chairman of Augusta National ducked under the ropes after Mickelson hit his approach. A sprinkler head next to the divot told Johnson what Mickelson had for his second shot on the 455-yard hole.
'He was 94 yards from the front of the green,' Johnson said. 'I was standing there when it rolled up, right by the 94-yard sprinkler. I went under the rope and went out to look at the sprinkler to see what was written on it.'
Mickelson's drive on No. 11 and Tiger Woods' drive on No. 18 in the final round -- he had only 75 yards to the hole, a simple lob wedge -- was all the assurance the chairman needed.
'That made me realize we were on the right track,' Johnson said during a recent interview. 'And it gave me incentive to be aggressive.'
The result was the most significant overhaul of Augusta National in its 68-year history.
There have been more drastic changes to certain holes over the years. A stream became a pond guarding the par-3 16th green in 1947. Two massive bunkers were added left of the landing area on the 18th fairway in 1967.
Still, Augusta has never had this kind of a facelift. Half of the holes no longer look the way they did when Woods won his second green jacket 11 months ago.
'We would like not to change the golf course,' Johnson said. 'The change in the game, and the change in the equipment, left us no choice.'
They left nothing to chance.
Most players routinely hit driver over the bunker down the first fairway. With the tees moved back 25 yards and the bunker extended about 15 yards toward the green, it now requires a 300-yard carry.
Should Mickelson hit that same drive on No. 11, you can bet he won't have a wedge into the green. Not only have the tees been moved back 35 yards, the left side of the fairway has been raised to make it more level, eliminating the slingshot effect off the right side.
If Woods has 75 yards left on No. 18, it will be his third shot. In perhaps the most drastic change at Augusta, the tees have been moved 60 yards back and the bunkers are 10 percent larger. To clear the bunkers on the fly is 335 yards.
The most fascinating change is No. 7, which is 45 yards longer. It's still only 410 yards, but is lined by tall Georgia pines on both sides and leaves precious little room for error.
'They used to hit 2-iron and 3-wood off the tee,' Johnson said. 'Then, they started hitting it so far and they realized the hole opened up down there, and they started hitting driver. And you saw what happened. They didn't have to worry.'
Johnson paused. He chooses his words carefully, and asked for a mulligan.
'I don't like to use that word, 'worry,'' he said. 'They're going to have to think.'
And that might be the greatest change at Augusta National.
'It isn't just the length,' Johnson said. 'The changes are going to make strategic value off the tee very important.'
Yes, power is important. It always has been and will be in golf.
But position is everything.
With the tees shifted 10 yards to the right and 20 yards back on No. 8, players will want to hit a slight fade. The ninth hole requires a slight draw. The 10th hole requires a big draw to stay out of the second cut of rough and reach the slope.
'In the past, it was a driving paradise,' Ernie Els said. 'Now, you've really got to get yourself in position and take it from there. You've really got to shape the ball.'
The advantage figures to go to the best driver, not necessarily the biggest driver.
Six of the last 10 winners at Augusta didn't exactly bomb it off the tee. Ben Crenshaw ranked 172nd in driving distance on the PGA Tour the year he won his second Masters. Mark O'Meara ranked 117th in 1998. Nick Faldo measured in at 120th in 1996.
Does the 285 extra yards help Woods, Mickelson and David Duval? It doesn't hurt, but if they're not hitting their driver well, it could lead to a long week - or worse, a short one.
'Whoever is driving the ball well and really putting well ... basically, whoever is playing well, it doesn't really matter if you're long or short at Augusta,' Woods said.
Augusta has never been a tougher, or more thorough, test.
When the changes were announced last year, Nick Price was asked what a stronger set of par-4s at Augusta National would mean.
'We'd have to use a few more brain cells,' he said. 'What little we have left.'