Former Vuelta a Espana winner Sean Kelly admits he is surprised to see Chris Froome enter this year’s race on the back of his Tour de France success, and believes Tour fatigue could hamper his ambitions in Spain.

Froome and Tour de France runner-up Nairo Quintana (Movistar) head the list of contenders for this year’s season-ending Grand Tour, with Vincenzo Nibali (Astana) also racing again.

But with those three, plus Quintana’s team-mate Alejandro Valverde, all racing on the back of their top four finishes at the Tour de France, Kelly believes the key will be who copes with the heat and fatigue best.

The Irish legend, winner in 1988, will be part of British Eurosport’s commentary team for the race – as he was at the Tour – and, though surprised at Froome’s decision to race, believes the Kenyan-born Brit will still be brimming with confidence.

“Fatigue is always a concern and when you succeed in the Tour, as Froome has done, I am surprised he is going to the Vuelta and taking the risk of suffering that fatigue.

“The Tour was a very difficult Tour, very aggressive racing all the time, that will catch up with him but he must feel very confident that he can challenge for the Vuelta victory also.

“I think it was a bit of a surprise when you consider he achieved what he set out to do this year – winning the Tour.

“[But] I think maybe the turning point was Quintana doing the Vuelta. I think maybe he wants to prove he can beat Quintana again.”

With the big mountain-top finishes crammed into the first fortnight, and a long time trial in the final week, the route certainly appears better suited to Froome than the Tour initially had.

The race, however, starts in Marbella and Kelly believes the heat – which Colombian Quintana is well versed in – could be an important factor.

“I think the route is not a problem for Froome,” the Irishman said. “I wouldn’t be concerned with that at all.

“The big concerns are will the Tour affect him, how well will he be supported and, I suppose, when you look at the Vuelta it’s a difficult one, starting down in Marbella, seven days in Marbella you could have seven days in the sauna at 40 degrees!

“And that is something that can affect you a lot if you have ridden a big Tour already, really battling in a three week Tour, well it can start hitting you then in the third week of the race.

“The heat will be a deciding factor, if we get that real, real warm conditions which you can get there it will make the race very difficult in the final week.

“Quintana can support that real, real warm weather, he can support it so well, it doesn’t seem to have any ill effects on him and I would say that he could have an advantage there.”

Froome is not the only Team Sky man racing the Vuelta on the back of the Tour either, with key domestiques Nicolas Roche and Geraint Thomas also back in action.

But Kelly has less concerns about those two, particularly as he believes Roche is still yet to hit top form for Sky.

“Nicolas Roche, for me, we didn’t see his best performance in the Tour as a domestique, but we have seen in the past, a number of years ago in the Tour he rides good but he rides better in the Vuelta.

“He has proved that when he was riding for himself and riding for his own place in the top ten in the GC. I think they feel he is going to be better than he was in the Tour, or certainly as good.

“Geraint Thomas, we know he can ride on and on, he is a solid rider and you can depend on him to do a good job in the Vuelta, I don’t think there is any doubt about that.

“So if those guys want to do the Vuelta and they have the morale to do it, then I would have no question about putting them in to the team because they are proven riders, they have proved it in the Tour this year but they have also proved it in the past, you look at both of them, real solid three-week race riders.”

Sky’s strength in depth is matched by their rivals, however, with Quintana and Valverde – second and third at the Tour – spear-heading a two-pronged Movistar attack.

Astana, meanwhile, have three potential GC men with Nibali joined by Giro d’Italia runner-up and third-place finisher respectively, Fabio Aru and Mikel Landa.

And Kelly thinks Nibali, who failed to match his Tour-winning performance of 12 months ago, should not be counted out of the running.

“I think Nibali could do a performance in the Vuelta,” he stated. “He won the national championships but didn’t get into the shape he was hoping to be for the start of the Tour.

“Then there are the other ones as well. It’s going to be interesting with Astana. Aru is going to be there also, then there is Landa. So Astana have three guys and, while I think Landa will definitely be used as a domestique when it comes to the crucial moment for the other two, if Aru is in good shape you have two guys from Astana who could be very much up there so they can cause a lot of problems for Froome and Quintana.

“Then there’s the rest of course. Let’s not forget Valvderde, Tejay van Garderen. The Vuelta has been so lucky the last couple of years.

“They get such a class field considering it’s the end of year. This year again they have almost all the big Tour potential winners.”

So where then, in Kelly’s opinion, will those potential winners be striking home their advantage?

The key, he says, will be the early mountain stages.

“I think the first mountain top finish in Andalusia is on day seven, that is going to be a difficult one early in the race, the warm conditions will have a big effect and if it’s really warm, I think we could see already riders losing a lot of time there.

“But again, the guys are going to be saying after the Tour ‘It’s very important that I rest up a bit and start the Vuelta as fully recovered as possible’ and that means little training.

“And that is the danger because then you come into the Vuelta first days and you’re not into that rhythm of racing it can take you maybe that first week to get back into it.

“[As a result] the mountain top finish on day five, that can be a vital one, that could be where we see some of the potential winners losing time.”

British Eurosport is the Home of Cycling and will show every stage of the Vuelta a España exclusively live from 22nd August to 13th September.