Historically, the Rays usage of the opener was not the first time a reliever started a baseball game. In the 1924 World Series, the Washington Senators sent out their starting pitcher, Curly Ogden, to pitch to the first two batters, and then a left-handed pitcher trotted in from the pen.
In another high leverage situation, the Pittsburgh Pirates attempted to throw off the Cinncinati Reds in the 1990 National League Champion Series. In an attempt to have the Reds change their batting order, the Pirates announced a left-handed pitcher, Zane Smith, would start the game instead of their right-handed scheduled pitcher, Ted Power.
And in what Ron Darling called “a precursor to all the things that you see today,” the Oakland Athletics planned on platooning their mediocre starting pitching staff for a brief six-game stint in the 1993 season. This sounds similar to Dave Fleming’s proposal for a 3-3-3 pitching rotation, meaning each pitcher would pitch three innings in a game.
Bryan Grosnick, a writer for SB Nation, proposed using an opener for the first inning or two before having the traditional starting pitcher enter the game. And in Brian Kenny’s 2016 book Ahead of the Curve, he identifies that the highest scoring inning in baseball is the first inning, so why wouldn’t a team want to shut down the opposition in the first inning with a reliable reliever?