The Spaniard, who withdrew from the Tour after two crashes, made a winning return to stage racing at his home race the Vuelta a Burgos last week, as Froome competes at the Rio Olympic Games.
And while Froome will be looking to add to his Tour triumph as well as a potential gold in the time trial in Rio on Wednesday, Contador will be looking to rescue his season with a win at the Vuelta.
Chris Froome congratulates Alberto Contador on his win in the 2014 Vuelta a España (Sunada)
No-one was able to match the Briton during the Tour de France, but Contador says Froome will not be unbeatable in the year's final Grand Tour, but it will be difficult to match the power of his Sky team.
"For me... it is more Sky than Froome [that is unbeatable]," Contador told Marca.
"Froome is obviously a very strong rider in both the time trial and on the climbs, but any rider can have a bad day. When you have a team where everyone can be a leader that makes it more difficult [for me]."
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33-year-old Contador will be eyeing a fourth win in his home Grand Tour, while Froome has never managed to take the top step, with his best results second place in 2011 and 2014.
Both will face further competition from the likes of Nairo Quintana (Movistar) who is set to return to racing at the Vuelta.
Becoming a trademark of the race over recent years, the route looks exceptionally difficult with 10 summit finishes, suiting the pure climbers.
"The Vuelta is not the easiest of the three [Grand Tours]," Contador said. "We are already seeing that there will be a great line-up this year with riders like Froome, Nairo, Valverde, Landa... The route has surprises for everyone. Each year that seems to be exceeded."
He looks set to sign with Trek-Segafredo for the next two years, although that has yet to be confirmed by the team. While Contador remained coy over the potential transfer, he wasn't quiet about voicing his ambitions of winning a third career Tour de France title before he calls it a day.
"What Trek team? I don't know anything yet of this signing, so we can't announce when this addition will be.
"It's clear for me: the Tour de France next year. It's my main goal. I think I have condition to do it.
"But before arriving there, I still have other challenges to achieve. It may not be in Rio, but in the Vuelta a España."
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