Quintana and Valverde are the only two riders to have already secured a spot in the squad, with twelve other candidates in the hunt for the remaining seven places.
Dowsett has started the Tour de France on one previous occasion, making it more than halfway round the 2015 edition before abandoning on stage 12 having suffered from injuries sustained in a crash earlier in the race.
The Brit will face tough competition to secure a spot in the final selection, with similar riders such as Daniele Bennati, Jonathan Castroviejo, and Imanol Erviti also being considered alongside mountain domestiques such as Carlos Betancur and Dani Moreno.
Full Movistar Tour de France shortlist
Nairo Quintana (confirmed)
José Joaquín Rojas
Alejandro Valverde (confirmed)