Let me tell you something about the Tampa Bay Rays' "opener" strategy: It was moderately controversial, and it required complete and total buy-in from the pitching staff. The pitchers had to be prepared to accept non-traditional roles, and had the players responded differently, the project might never have gotten off the ground.
Let me tell you something else about Tampa Bay's opener strategy: It sure seems like it's worked. The Rays were 21-22 when they started Sergio Romo for the first time on May 19. Since then, they've had one of baseball's top-10 records. More impressively, through May 18, the Rays' pitching staff ranked 22nd in baseball in ERA. Since May 19, they've ranked second, behind only the Los Angeles Dodgers. Sure, Blake Snell has been great, and the Rays haven't completely abandoned traditional starting pitchers. But the opener has been there more often than not, and the Rays haven't looked back. They're likely to keep using the approach in 2019.
The Rays kind of stumbled into this position -- had it not been for bad luck on the injury front, they might have gone with a more conventional staff. But the Rays have learned something, and as soon as a concept catches on in one place, it's more likely to catch on elsewhere. The Oakland Athletics, for example, have recently used Liam Hendriks as an opener. When considering something daring, most teams would rather be second than first. You don't run as much risk of looking stupid. The opener is out there now, so other teams will be more comfortable giving it a shot.
Which makes me wonder if we might see it in the playoffs. Barring the near-impossible, the Rays won't be in the postseason, but that doesn't mean they can't have an influence. We've seen pitching staffs managed in non-traditional ways in Octobers past. What if the opener made an appearance? Which contending teams might be best suited to give it a try?