Complex sentence: On August 15,2012, Hernandez threw the first perfect game in Mariners history and 23rd in Major League Baseball history against the Tampa Bay Rays, with 12 strikeouts in a 1-0 victory.
Split into simpler sentences: On August 15, Hernández threw the first perfect game in Mariners history and 23rd in MLB history. He recorded 12 strikeouts against the Tampa Bay Rays in a 1-0 victory.