Another big factor are likely to be the bunkers, which Nicklaus has made more punitive by the introduction of an unconventional, long-toothed wooden rake.

The rake, which has tines two-and-a-half inches long and widely spaced apart, creates gouges in the bunkers to make recoveries more difficult.

"Bunkers are really supposed to be a penalty," said Nicklaus, who is not playing this week after being the only player to compete in each of the previous 30 Memorial tournaments.

"All I'm trying to do is make the guy think he doesn't want to be in the bunker, and it's not the place to aim for."

BUNKER CHALLENGE

Jim Furyk, the world number five and Memorial champion in 2002, expects a challenge.

"I think it's going to be extremely hard out of the fairway bunkers, you're not going to see a lot of guys hit greens out of those bunkers," the 36-year-old said.

"It's going to be interesting, because there are some severe bunkers out here and severe greens."

American Bart Bryant, who won last year's Memorial by a stroke from Fred Couples, is back to defend and, like Els, has targeted an improvement in his putting.

"I haven't played great this year," said Bryant, who has produced just one top 10 in 12 PGA Tour starts this season.

"I feel like if I can get my putter worked out, get some issues fixed that I might have a chance to recapture some of that magic that I had last year."

The tournament starts on Thursday.