UNIVERSITY PLACE, Wash. -- In a unique twist for any golf course, Chambers Bay will see the first and 18th holes play as either a par-4 or a par-5 during the U.S. Open.

But the players will be unaware until they arrive each day what they will face on the opening and closing holes that run parallel to each other.

"I know that there's probably some saying, 'Why did you change up the par at 1 and 18 -- what gives?'" said Mike Davis, executive director of the United States Golf Association. "The way the architects designed the holes, truly they did it with flexibility in mind. And we looked at it and say these holes are great played as both a 4 and a 5. They're two completely different drive zones if both holes played 4 and 5.

"The greens can be very severe and almost add the element of risk and reward with hole locations. The bunkering is different. We went into it thinking this is going to be the right thing to do. There's going to be a 100-yard difference playing between a 5 and 4 on those holes."

Chambers Bay will play between 7,300 and 7,700 yards, Davis said, with par of 70. If the first hole is deemed a par-4, the 18th will be a par-5 and vice versa. It is possible they could change daily, based on weather conditions.

The 18th hole at Chambers Bay can play as either a par-4 or a par-5 and may alternate between the two during the U.S. Open. AP Photo/Ted S. Warren

Davis said the players will learn of the hole distances and pin positions each day, as would be the case at any tournament.

The first can play anywhere from 496 yards to 598 yards. The 18th is listed as 525 to 604.

"Think of it this way, those two holes are really a par 9, but we're going to give that trophy to the lowest 72-hole score," Davis said. "Whatever the par is in some ways is irrelevant.

"As far as the rest of the teeing grounds, many of the players this week have already been practicing from different teeing grounds. I think they know it. They may not have gotten everyone, but they know we're going to move things around."

That is why players have spent so much time trying to learn the course.

"None of us, none of you guys in this room, none of the players, know what Mike is going to do on the setup," said Tiger Woods, referring to Davis and a team of USGA officials who determine tees and pin placements as well as whether or not to put water on the course. "We don't know what Mike is going to do on the different winds and the different days. We could say long hitters have an advantage, but maybe not. Depends on what Mike does."

Hearing that makes Davis cringe to a degree.

"There is a lot of flexibility to this course, so we can do a lot of things with the setup," he said. "And we will do that in a very reasonable way."

The USGA also announced that the purse for the U.S. Open will be $10 million, a $1 million increase over last year's tournament won by Martin Kaymer at Pinehurst No. 2. The Masters, the Players Championship and the PGA Championship also have $10 million purses.