"Just got the best call of my life!!!!" he wrote. "It's show time!!!"
Rodriguez, 25, has gone 4-1 with a 3.40 ERA, 1.19 WHIP and 53 strikeouts in 50.1 innings for the Triple-A Sacramento River Cats this season. He was drafted by the Minnesota Twins in the sixth round in 2011 and joined the Giants farm system as a free agent this season.
He started his career as an outfielder but made the shift to pitching in 2014.