Classics rider Thwaites, 24, was one of 14 riders on the longlist of German wild cards NetApp Endura but it was confirmed this morning that he has not made their nine-man team.
He is however, one of two reserves and will be called up in case of illness or injury to one of the starting nine, prior to the race.
His fellow Yorkshire riders Ben Swift and Josh Edmondson are also expected to miss out when Team Sky name their squad.
NetApp’s team: Jan Barta (29 / CZE), David de la Cruz (25 / ESP), Zak Dempster (26 / AUS), Bartosz Huzarski (33 / POL), Leopold Koenig (26 / CZE), Tiago Machado (28 / POR), Jose Mendes (29 / POR), Andreas Schillinger (30 / GER), Paul Voss (28 / GER).
Reserves: Iker Camano (35 / ESP), Scott Thwaites (24 / GBR).