The Basque squad announced on its website the five riders who will definitely start Spain's Grand Tour; Igor Antón, Beñat Intxausti, Egoi Martínez, Gorka Verdugo and Mikel Nieve have been guaranteed places in the nine-man roster.
Sanchez, who finished second overall last year (behind the now-suspended Alejandro Valverde) and third in 2007, recently took fourth at the Tour de France, only missing a place on the final podium courtesy of the final time trial, where Denis Menchov leap-frogged his Spanish rival to finish third in Paris.
The day before that time trial he had fractured the radius of his right hand, although remarkably he still managed a commendable ninth in last weekend's Clasica San Sebastian.
Last week, Foundation Euskadi President Miguel Madariaga told Europa Press: "Samuel is on the list of reserves for the Vuelta, but is not yet time to say whether he will participate or not.
"You have to recover from the fracture you have. After San Sebastian we'll know if Samuel is able to continue training and riding a bike."
Sanchez has been the subject of recent speculation - Spanish media reports on an apparent bid for his signature by Dutch Pro Continental squad Vacansoleil as it seeks a Grand Tour start in 2011. There's no news as to the likelihood of his transfer, although the offer was substantial, according to El Diario Vasco.
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Koldo Fernandez de Larrea, Javier Pérez, Alan Aramendía, Pablo Urtasun, Juanjo Oroz and Amets Txurruka are the other candidates for positions in Euskaltel-Euskadi's Vuelta starting line up, the latter two questionable starters as they recover from injuries suffered during the Tour.
