Tour de France hopefuls Chris Froome, Vincenzo Nibali and Nairo Quintana enjoyed varying fortunes at the Fleche Wallonne one-day classic in Belgium.

Reigning Tour champion Nibali showed he was in good form, attacking the field on the penultimate climb 5km from home before battling shoulder to shoulder with the favourites up the Mur de Huy finish in Wallonia on Wednesday.

The Italian finished 20th at the end of the 205.5km Ardennes Classic race at just 19sec of Spanish winner Alejandro Valverde.

However, earlier in the day, there was speculation that Nibali might join Vuelta a Espana champion Alberto Contador in riding May's Giro d'Italia.

Nibali's compatriot and Astana teammate Fabio Aru was due to ride the Giro as team leader but had to pull out of this week's Giro de Trentino due to a stomach virus and is now a doubt for the Tour of Italy.

A report in La Gazzetta dello Sport quoted Nibali as saying he may ride the Giro, particularly with the ongoing uncertainty about Astana's World Tour licence over several doping cases and the possibility it could be revoked.

Gazzetta speculate that Nibali, 30, might opt to ride the Giro as a safety net, in case the licence is withdrawn between May's Giro and July's Tour.

"It's true. Martino (Astana manager Giuseppe Martinelli) is pushing for me to ride the Giro too. But at the moment it's not in my plans," said Nibali.

With Contador already deciding to go for a Giro-Tour double, the prospect of Nibali doing likewise would certainly excite Giro organisers.

Particularly with Australian Richie Porte showing his form in taking control of the Giro del Trentino on Wednesday after a solo victory on the second stage, to back up his impressive overall victories at Paris-Nice and the Volta a Catalunya stage races.

A half-fit Aru would likely be no match for Porte or Contador but a Nibali firing on all cylinders would.

While Nibali proved his form in Belgium, the same could not be said of Froome.

The 2013 Tour de France winner, who crashed out last year inside the first week, was on the deck again in Belgium.

Froome crashed inside the final 10km and although he carried on to the finish, he lost more than 12 minutes and came home 123rd.

"Chris was... pretty banged up but showed real courage to finish the race and we'll assess his injuries overnight," said Team Sky sports director Gabriel Rasch.

"He hasn't needed to go to hospital and right now as things stand, we're still expecting him to line up at the Tour de Romandie next Tuesday.

Froome, 29, was still due to ride the cobbled section that forms part of the Tour's fourth stage on Thursday as a reconnaissance mission.

The Kenyan-born Brit started his season well by winning the Ruta del Sol but he then had to pull out of Tirreno-Adriatico in early March due to a chest infection.

On his comeback at the Volta a Catalunya, he struggled and finished almost 40 minutes behind Porte in the overall standings.

As for Quintana, he seemed to be on a voyage of discovery at Huy, following Movistar teammate Valverde's wheel throughout.

The third stage of July's Tour finishes at the top of the Mur so Wednesday's race was useful in terms of intelligence gathering.

Quintana, 25, sat up once the racing spiced up and finished 76th at 2min 43sec.

The Colombian may have been giving little away but he has already demonstrated his condition, winning Tirreno-Adriatico at a canter.
Source: AFP