Complex sentence: The Mets and Royals are set to meet on April 4 for Opening Day 2016 in Kansas City, which will mark the first time ever that the previous year's World Series contenders meet on Opening Day.
Split into simpler sentences: The Mets and Royals are set to meet on April 4 for Opening Day 2016 in Kansas City. This will be the first time ever that the previous year's World Series contenders meet on Opening Day.