Rule 5 Draft choice in 2005 and started the year playing for the Potomac Nationals. Blanco was invited to spring training for the big league club and quickly made it to the roster early in 2005, playing in 56 games. During 2005, his rookie season, he hit .177 with one home run and seven RBI
.
In
Dominican Winter League for the Estrellas Orientales. He was then acquired by the Chunichi Dragons, who released their cleanup hitter Tyrone Woods
due to his high wage, shortly after that.
His first year in NPB was very successful,[
Nagoya Dome(first in dome history), hitting the light unit above the advertisement board in Tokyo Dome
, as well as hitting the top-level stand in the Nagoya and Osaka Domes. He finished his first season with an impressive 39 HR and 110 RBI, both leading in Central League, along with a .275 batting average. Other than the HR and RBI award, he was also rewarded as Central League Performance Award in Interleague game (11 HR and 24 RBI) and won the Home Run Derby before the All-star game (which he was also playing as Central League first baseman).