Michael Boogerd and Erik Dekker have a job on their hands if they are to win the only Dutch one-day classic in the 27-leg Pro Tour series, the Amstel Gold Race, which takes place Sunday in Maastricht.

Boogerd, the winner in 1999, and reigning Paris-Tours champion Dekker, the winner here in 2001, are among the favorites for the 250.7km race, especially as a host of other contenders have opted out of the ProTour's eighth race.

ProTour series leader Tom Boonen (Quick Step) - the recent winner of the Tour of Flanders and Paris-Roubaix last week - is among those giving Amstel Gold a miss. Joining the 24-year-old Belgian on the absentee list are Peter Van Petegem (Lotto) and Juan Antonio Flecha of Spain and Italian sprinter Alessandro Petacchi (Fassa Bortolo).

Still, there will be strongmen aplenty, including Spanish sensation Alejandro Valverde, Italian Danilo Di Luca, Kazakh Alexandre Vinokourov, Luxemburger Kim Kirchen, and Italy's reigning champion, Davide Rebellin.

Last year, Rebellin outsprinted Boogerd to begin an unprecedented three-race winning streak in the Ardennes one-day classics, which he followed with victories at the Fléche Wallone and Liège-Bastogne-Liège.

Rebellin, who rides for Gerolsteiner, has been relatively quiet all season. But his second place overall in the Tour of the Basque country behind compatriot Danilo Di Luca (Liquigas) is testament to his form.

The 33-year-old Rebellin comes into the race well-suited to Amstel's 31 medium-sized climbs, which could prove more problematic for the rest of the peloton.

Jan Ullrich will not be racing, but T-Mobile will be sending Vinokourov, Matthias Kessler, Steffen Wesemann and Erik Zabel.

Kessler could prove their main contender, the German having come fifth in 2003 and sixth last year, although Vinokourov would not object to repeating his victorious finale of 2003.

T-Mobile will also field local rider Bas Giling, who has been riding strongly in the past weeks and has the advantage of knowing the undulating route in Limburg, the region sandwiched between Germany and Belgium.

"I know every climb on this course. I train regularly on these hills," said the young Dutchman.

Another contender is American George Hincapie (Discovery Channel), whose second place behind Boonen at Paris-Roubaix last week was the closest the 31-year-old New Yorker has gotten yet to lifting the fabled cobblestone trophy in years of trying.

Hincapie may find the going tough again on a route that, although devoid of Roubaix's suicidal cobblestones, has plenty of other challenges.

Nevertheless, his team manager Johan Bruyneel is upbeat.

"George is in great shape," he said. "He's never done very well in the few times he has taken part in the race because it used to be the last race of the spring. Now, I think he's fresher at this stage."

Still, Rebellin will be the man everyone is watching out for, especially Boogerd. The Dutchman was on course for victory last year until the cagey Italian outsprinted him ahead of the finish line. It was Boogerd's fourth podium finish in the race since 2000, and his second runner-up place in as many years.