Fabregas named in Spain squad
Del Bosque said Fabregas was recovering well from a hamstring strain and Arsenal had said he could feature against Manchester United in the Premier League on Saturday.
Senna of Villarreal, a key member of last year's European Championship-winning side, has been sidelined since April with a leg muscle problem but is approaching full fitness.
European qualifying Group Five leaders Spain play Belgium in La Coruna on September 5 and Estonia in Merida on September 9.
Goalkeepers: Iker Casillas (Real Madrid), Pepe Reina (Liverpool), Diego Lopez (Villarreal).
Defenders: Raul Albiol (Real Madrid), Alvaro Arbeloa (Real Madrid), Joan Capdevila (Villarreal), Carlos Marchena (Valencia), Gerard Pique (Barcelona), Carles Puyol (Barcelona), Nacho Monreal (Osasuna).
Midfielders: Xabi Alonso (Real Madrid), Sergio Busquets (Barcelona), Santi Cazorla (Villarreal), Cesc Fabregas (Arsenal), Xavi (Barcelona), David Silva (Valencia), Juan Mata (Valencia), Albert Riera (Liverpool), Marcos Senna (Villarreal).
Forwards: David Villa (Valencia), Daniel Guiza (Fenerbahce), Fernando Torres (Liverpool).