To make room for him on the 25-man roster, the Giants optioned outfielder Jarrett Parker to Sacramento.
"We just needed the coverage," Bochy said. "Hopefully nothing happens, but if it does, he can go 100 pitches. So he gives us a fresh arm. That game [Wednesday] caused a lot of extra work for the rest of our guys. It forced us to make this move to get another arm up here."
Bochy couldn't say at this point whether the move was for the long or short term.
"I don't know for sure. I don't have that answer," Bochy said. "We'll see how it goes."
In any event Blackburn, who hails from just outside Oklahoma City, was ecstatic about being called up to the Majors for the first time.
"I got the phone call [from Giants general manager Bobby Evans Wednesday] night [in Sacramento], and obviously it being the first time, it was quite the phone call to receive," Blackburn said. "The fun thing was calling my friends and family. They were more excited than I was."
Giants second baseman Joe Panik made his Major League debut at Chase Field on June 14, 2014, and Blackburn said he was in the stands that night. His father Brian, mother Kerry and brother Colton made the trip from Oklahoma and were at Chase Field in case Blackburn pitched in his first big league game.
Like just about every young player, Blackburn said it was "a dream come true."
"Since I was a 4-year-old throwing the ball around the front of the house," he said.
At Sacramento this season, he was 1-3 with a 5.68 ERA in seven appearances (six starts).
Barry M. Bloom is a national reporter for MLB.com and writes an MLBlog, Boomskie on Baseball. Follow @boomskie on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.