Blanco logged three scoreless innings against the visiting Oakland Athletics, allowing four hits and one walk with four strikeouts. Crew chief Laz Diaz ejected Blanco after his glove was confiscated and inspected between innings.
Astros manager Joe Espada offered a mild protest but quickly acquiesced as Blanco retreated to the dugout and home clubhouse.
Blanco entered his eighth start of the year with a 4-0 record and a 2.23 ERA. He made the rotation out of spring training, primarily due to right-handers Justin Verlander and Jose Urquidy opening the season on the injured list. Blanco fired a no-hitter in his first start of the season against the Toronto Blue Jays on April 1.
Blanco, 30, owns a career 6-1 record with a 3.58 ERA in 32 career games (15 starts) across three major league seasons, all with the Astros.
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The Astros went on to win the game, 2-1, in 10 innings.