The Vuelta a Espana may have a reputation as a revenge race for riders who missed out in the Tour de France but there won't be much redemption in the air ar this year's Spanish grand tour. Instead, the race has attracted a formidable line-up of grand tour stars who travel to Spain on the back of what has mostly been highly successful seasons. Giro champion Vincenzo Nibali (Astana) and local heroes Joaquim Rodriguez (Katusha) and Alejandro Valverde (Movistar) have attracted most pre-race interest but they will have to contend with exciting talents Sergio Henao (Sky), Carlos Betancur (Ag2r), Rigoberto Uran (Sky), Thibaut Pinot (FDJ) and Rafal Majka (Saxo-Tinkoff) and accomplished grand tour veterans Michele Scarponi (Lampre), Ivan Basso (Cannondale) and Samuel Sanchez (Euskaltel). Defending champion Alberto Contador and the best two riders from the Tour de France may be absent but apart from that Vuelta organizers Unipublic could hardly have imagined a stronger line-up for their race. CyclingQuotes.com takes a thorough look at this year's favourites and outsiders and finds out all about their strengths and weaknesses.

Last year's Vuelta a Espana evolved into a local battle between the three Spanish grand tour giants Alberto Contador, Joaquim Rodriguez and Alejandro Valverde but this year's race should have a much more international flavour. Valverde and Rodriguez are back after having impressed in the Tour de France but those two join Samuel Sanchez on the list as the only genuine Spanish winner candidates.

Italy's three grand tour winners Vincenzo Nibali, Ivan Basso and Michele Scarponi have all made the Vuelta a prime target and a host of exciting Colombian talents are ready to continue their recent domination. On a course that offers no less than 11 uphill finishes, such a bunch of climbers can only create a very exciting bike race and the race could very well shape up to be the closest of this year's grand tours.

CyclingQuotes.com has taken an in-depth look at the race's favourites, assigning 5 stars to the race's biggest favourite, 4 to his two biggest rivals, 3 to three other potential winners, 2 to four of the podium contenders and 1 to 5 of the race's minor outsiders. In this article, we take a look at the 3-star favourites that may be seen as genuine winner candidates.

Alejandro Valverde (***)

No one can take away from Alejandro Valverde that he is a classy grand tour rider who has made a huge impact on the Vuelta a Espana ever since his breakthrough 3rd place as a young Kelme rider back in 2003. Since that year he has finished in the top 5 whenever he has lined up at his home grand tour, having only missed the event in 2005 and in 2010 and 2011 due to his doping suspension, and he even won the race in 2009.

Earlier in his career, Valverde was famously known for his bad days in the mountains that often left him with no winning options. He almost overcame those difficulties in the 2009 Vuelta and since his comeback from suspension, he has improved his consistency even further.

His natural abilities may make him more of a classics specialist than a grand tour rider but as is often seen, he has improved in the three-week races with age. He has made a quantum leap forward since he came back from suspension. During the first months of his post-ban career, he had difficulty competing with the best over longer distances but the 2012 Tour de France put his endurance back up to its best level. Crashes were one of the reasons for his less successful comeback grand tour but his two most recent showings have been the best of his career.

Last year he was only slightly below the level of Alberto Contador and Joaquim Rodriguez in the Vuelta mountains and had it not been for a crash on stage 4, his consistency may even have been enough for him to win the race. This year he did his best ever Tour de France and only lost what would have been an almost guaranteed podium spot when he had a mechanical on the stage to Saint-Armand-Montrond.

This year's mountainous route suits him perfectly. The many uphill finishes allow him plenty of opportunities to shine and he is likely to be the rider to benefit the most from the bonus seconds. While he may be unable to match Rodriguez and Henao on the very steep ramps, he is the - by far - best sprinter among the GC riders. That ability allowed him to win two stages last year and he should pick up at least one win again this year and so bolster his GC chances by virtue of bonifications.

The hilly time trial suits him well and if he can live up to his recent standards, he may even gain time on some of his rivals in the race against the clock. He finished 5th in the hilly Tour time trial and 4th in last years' Vuelta race against the clock but his stand-out performance was probably his 13th place in the flat first time trial of this year's Tour. Movistar is one of the best teams for team time trials - they even won that stage in last year's Vuelta - and while they may have preferred a more selective and technical course, they should not be too far off the mark on day 1. At the same time, riders like Benat Intxausti, Eros Capecchi, Sylwester Szmyd, Jose Herrada and Javier Moreno will provide a fantastic support in the mountains that is maybe only surpassed by Nibali's formidable Astana squad.

While this all suggests that Valverde should be in winning contention, the Tour de France also revealed his limitations. Valverde has probably never been stronger than he was during the Tour and nonetheless he was below the level of Chris Froome, Nairo Quintana and Joaquim Rodriguez. He will have to go up against the latter once again in the Vuelta while Vincenzo Nibali and Sergio Henao have also come into the mix. Valverde may very well finish on the podium but it is doubtful whether he actually has the capabilities to win the race.

Furthermore, he will have to battle the same challenge that is also Rodriguez' main weakness. The Tour-Vuelta double is no easy task and no rider has finished on the podium in both events since the hugely consistent Carlos Sastre did so in 2008 and Joseba Beloki is the only other rider to accomplish the feat in the 2000s. Like Rodriguez, Valverde has tried to prepare as best he could by limiting his early-season racing but he has still had a fairly heavy race schedule and couldn't resist the temptation to ride the Clasica San Sebastian in between his two grand tours, finishing 2nd in his home classic. He is likely to pay the price somewhere during the hard three-week race.

Compared to Rodriguez, Valverde has one major advantage. He has plenty of experience in doing  the Tour-Vuelta double - even though it's striking that he won the race in the one year he didn't do the Tour. At the same time, he has a history of performing strongly in the second part of the season and it is no coincidence that he has finished in the top 5 whenever he has reached Madrid and performed well at numerous world championships. Valverde may be the rider who has the best chance of going for the double but it remains a question whether his top level will ever allow him to once again win a grand tour.

Carlos Betancur (***)

Based on his performances last year, it was a surprise that some of the big teams hadn't singled out Carlos Betancur as one of the riders for the future and that no one entered the hunt for the Colombian talent's signature late last season. Instead, it was Ag2r who signed a contract with the huge talent and they probably mostly did so in an attempt to bolster their points tally.

However, Betancur has emerged as one of the best climbers in the world during his first season as a ProTeam rider. Having already dominated the Italian racing scene last year, he has gone on to compete with the best in the biggest races right from the beginning.

He had a slow start to the season but by the time of the Vuelta al Pais Vasco in early April, his legs had finally started to come around. He was only narrowly defeated by Henao in the very steep uphill finish on stage 3 and did a good time trial on the final day to finish 7th in the hilly race.

From then on his legs only got better. His surprise attack on the Mur de Huy nearly gave him the win in the Fleche Wallonne and he still held on to 3rd. A few days later he finished 4th in the Liege-Bastogne-Liege but his real stand-out performance came at the Giro.

Betancur finished 2nd on three stages and emerged as the second-strongest climber in the race, only surpassed by race winner Nibali, and proved an amazing consistency. If it hadn't been for his massive time loss on the long time trial and his unfortunate crash on the descent on stage 3, he would have taken a comfortable 2nd place in his second grand tour, the first as a GC rider.

His qualities as a climber marks him out as a red-hot podium candidate on a course with 11 uphill finishes, many of those extremely steep. He is punchy, reliable on longer climbs, not afraid of aggressive racing and thrives when the road gets really steep as his performances in the Vuelta al Pais Vasco and the Fleche Wallonne underline. In the Giro, his fast finish allowed him to pick up many bonus seconds and he may do the same in Spain despite the higher level of competition in his favoured kind of finishes.

Betancur's main weakness is his time trial which may be what costs him a genuine winning opportunity. The time trial may only be 38,8km and contain a hill but nothing suggests that he will not lose time to his main rivals on that day. He lost 4.58 to Nibali in the flat Giro time trial and while that one was longer and not as hilly as the one in the Spanish grand tour, he can expect to have some time to make up in the second part of the race. He should also lose time in the team time trial as a similar Ag2r team lost 36 seconds to Astana in the Giro TTT which was shorter and much more difficult. On the flat course for stage one and against a stronger Astana team, Betancur's French team should lose even more time to the main favourite.

Those time losses may, however, give Betancur the chance to do what he does best: attack. Surprisingly, he has also been overlooked as a genuine GC contender and that may allow him to slip up the road while the GC riders look at each other. That could backfire on the main contenders who would do themselves a favour by keeping a firm eye on the small Colombian.

The main question surrounding Betancur is his ability to handle two grand tours. He has never tried such a daunting task in the past and no one knows how he will handle the strains of so much racing. Furthermore, no one knows anything about his current condition. He hasn't raced since the finish of the Giro and so will start the race with no recent racing in his legs. Instead, he has prepared himself on his own in his native Colombia but that decision may backfire in a race that has a tough uphill finish already on stage 2. On the other hand, Nairo Quintana had a similar preparation for the Tour de France and everyone should remember the result of that experiment.

Michele Scarponi (***)

When Michele Scarponi last year failed to live up to expectations in his defence of the 2011 Giro title and took a hugely disappointing 4th place and when he was almost invisible the rest of the year - despite a number of breakaway participations in the Tour de France - it was easy to write off the Italian as a remnant of the past. Determined to prove his critics wrong, the 33-year old has let his legs do the talking this season and while he may not be back at his 2011 level, he has been a constant presence in the biggest races.

Due to his relation to banned doctor Michele Ferrari he was banned for three months during the off-season and new sponsor Merida kept him away from competition in the early part of the season, fearing bad publicity. It took a concerted effort from Scarponi's lawyers to land a deal which allowed him to return to racing and part of the agreement is that his contract will be terminated at the end of the season.

As soon as he lined up in a race, he did, however, prove that he had done his homework.  Few riders have been hampered by bad luck to the same extent as Scarponi and so his results are not there to show his strength. He punctured out of the Paris-Nice GC when a top 10 result was all but secured. He crashed twice in the Tour de Suisse when he appeared to be one of the strongest riders in the race. And in his biggest season objective, the Giro d'Italia, the skinny Italian suffered from the extremely cold conditions and lost time due to an unfortunate crash on stage 3. Nonetheless, he still managed to finish 4th and eventual winner Vincenzo Nibali repeatedly referred to Scarponi as the most impressive rider on the climbs. Furthermore, he ended up 3rd in the Volta a Catalunya, 2nd in the Italian championships and was one of the strongest riders in Liege-Bastogne-Liege.

His lack of results may now be a blessing in disguise. Scarponi has barely been mentioned in the pre-race analyses and that could allow him to fly under the radar in the early part of the race. However, his rivals cannot allow themselves to neglect one of the few riders who has proved that he has what it takes to win a grand tour.

With its many uphill finishes, the route suits him perfectly. He is an explosive rider who excels on those short, steep climbs that characterize the Vuelta, having been the big favourite on those kind of finishes during the 2011 Giro. He has performed well on the steepest climbs in the Giro in the past and has a nice track record on the Monte Zoncolan. His main weakness in the mountains is his tendency to go too deep too early, often blowing up as a consequence. That may pose a problem against explosive climbers like Rodriguez, Valverde, Henao and Betancur and he has to gauge his effort better than he has done in the past.

Earlier in his career, he lost much time in the time trials but this he has improved immensely in the race against the clock. He even finished 10th in the long Giro time trial which would have been unheard of earlier in his career. With Diego Ulissi, Winner Anacona and Simon Stortoni on the roster, his Lampre team shapes up to be a force to be reckoned with.

The main question is his current condition. Since the Italian championships, he has only raced once when he delivered an anonymous performance in the Tour of Poland. That may not be a problem - he didn't perform well in the Giro del Trentino but still lined up in the Giro in splendid condition - and he claims to have trained well since.

Another question is his level of motivation. He has no strong track record in the autumn season and has a tendency to disappear in the second half of the season. When he last tried the Giro-Vuelta double in 2011, he ended up abandoning the Spanish grand tour. With a world championships on home soil coming up later in the year and an uncertain future, he may this time  have an extra incentive to perform well and it is not impossible that the Vuelta will be the race that brings Scarponi back into the spotlight as a grand tour rider