seems to be working for Tampa Bay... https://www.si.com/mlb/2018/08/23/tampa-bay-rays-bullpen The Rays debuted the opener—in which a reliever starts the game and throws anywhere from one to three innings, then gives way to a new pitcher, who will usually throw three to five as essentially a second starter—on May 19 against the Angels, using veteran righty Sergio Romo to pitch the first. They haven’t looked back since. Across the last four months and 84 games, 50 starts have gone to eight different relievers: Romo, Ryan Yarbrough, Ryne Stanek, Hunter Wood, Wilmer Font, Jonny Venters, Matt Andriese, Diego Castillo, and Yonny Chirinos. As openers, they’ve combined for 93 innings and 41 earned runs—a 3.97 ERA, or better than the league average of 4.15.