It would be foolish to suggest that the International, starting in Castle Rock, Colo., today, acts merely as a warm-up for next week’s PGA Championship at Baltusrol. So rather than going all out for another tour victory, the brightest lights in the field will probably be content to bring their games up to speed in the heat of serious competition while working on shots that the historic Lower Course will demand next weekend.

It must be said, however, that the International, celebrating its 20th anniversary this year, could hardly be considered the ideal tone-up for the year’s final major. The field is certainly a strong one, with 10 of the world’s top 19 golfers committed, but Castle Pines, the wonderful Jack Nicklaus design, sits well over 5,000 feet above sea level, meaning shots fly significantly further – 10-15% further on average – than they will at Baltusrol. Two hundred yards might call for a 6-iron or 7-iron this week, while a 5-iron might be required to send the ball a similar distance in seven days’ time. Sure, those playing in the PGA will have a couple of practice rounds at Baltusrol to get used to the atmospheric conditions before the bell rings on Thursday, but having to deal with that is perhaps something a pro golfer’s brain and sensory department would be better off without.

Then there’s the modified Stableford scoring system, unique to the International, which awards five points for an eagle, two for a birdie, minus one for a bogey, and minus three for a double. With added incentive to attack and relatively painless consequences should they end up in the drink, players are encouraged to fire at pins they might otherwise dance around and take on shots they certainly wouldn’t even consider attempting at a major.

At 7,392 yards with 25-yard wide fairways and lush, four-inch bluegrass rough, Baltusrol will be the genuine article – a stern, major championship test requiring solid ball striking, carefully thought-out strategy, and a tendency toward patience and caution. In short, the challenge next week couldn’t be any more different from what players will face in Colorado today.

But with $5 million to play for, and places on the President’s Cup team and qualification for the season-ending Tour Championship to think about, there are still plenty of reasons for players to head west this week.

With two wins, two second-place finishes, and a total of 286 points in 12 appearances, the favorite this weekend is likely to be Phil Mickelson, who skipped this event last year to prepare for the PGA Championship.

It’s a bit surprising, perhaps, that he chose to play this year, but a win would do wonders for his confidence, which has surely dipped considerably in the wake of some disappointing recent results. Not since winning the Bell-South Classic in Georgia during the first week of April has Mickelson seriously contended, and his performances at the U.S. and British Opens did nothing to excite his legions of fans, either.

Thanks to some stellar early season form, however, Lefty is second in the birdie table this year with 4.61 per round, and he obviously enjoys the Rocky Mountain air, so teeing it up this week might well be a shrewd move on his part. Should he arrive in New Jersey with a fourth win of the season under his belt, he will be in a good position to double his number of career major victories.

Also in need of a boost following his dismal fourth-round 81 at the U.S. Open and equally frustrating Sunday disappearing act at the British is Retief Goosen. The South African finished runner-up to Davis Love in 2003, his only other appearance at the International, and a performance like that would do much to restore his poise in time for next week.

Other contenders include Sergio Garcia, whose aggressive style appears tailor-made for the format, and Chris DiMarco, who has a third, a fourth, and a sixth in the last four years here. Staying away are Tiger Woods and Vijay Singh, who put on a thrilling show at last weekend’s Buick Open.

Both are home, readying themselves for what they know will be a grueling test next weekend.

Mickelson and the rest of the stars playing this week know what they’re doing, of course. But unless they win the International and head to Baltusrol full of confidence, one has to wonder if, given the profound differences between the location and style of this week and next week’s tournaments, the range at home might not be the best place to play.