Cody Allen had a rough first two weeks to the season, turning a tie game into a 4-run deficit in the 9th inning of his second appearance of the season, and then blowing a 3-run lead in his fifth outing. He gave up four runs in each of those games, giving him an unattractive ERA of 18.00. That led many Tribe fans (including a number here at LGT, where we're supposed to be more enlightened than the average yokel) to conclude his workload the last couple years had broken him, and that he should be moved out of the closer role.
Since that point, Allen has appeared in another 28 games, and has allowed a batting average of just .180 and an OPS of just .512. His ERA over that time is 1.55, and he's struck out nearly five times as many batters (44) as he's walked (9). Turns out he wasn't broken, and didn't need to be removed from the closer role.
Moving the cutout back a bit, since allowing one run in a non-save situation on May 10, Allen has allowed only 2 runs in 21 appearances, giving him an ERA of 0.82 over those seven weeks, during which he's allowed only 17 base runners in 22 innings. It isn't as though he's been relying on tremendous defense behind him to post those numbers either, instead he's gotten 35 of his 66 outs over that time.
In June, Allen was the best reliever in baseball. He allowed 0 runs in ten appearances, giving up only 5 singles and 2 walks the entire month, for an OPS allowed of just .353. He compiled a staggering 20 strikeouts from among the 32 total outs he recorded, that 16.9 per 9 innings, which is tied for the 11th-highest figure for any month in American League history.
Allen has zero chance of making the All-Star Game, in part because the Indians haven't given him many save opportunities, and in part because despite his 1.55 ERA since those first two weeks of the season, those two terrible games mean his actual ERA right now is still a modest 3.55. I'm not arguing that those two games shouldn't count, but it's instructive to see that halfway through the season, two games still make someone who's been fantastic look average.
Allen's season goes a long way to point out the problem with ERA for relievers. Without those two games, Allen's ERA would be 1.41, instead it is more then two full runs higher.
Allen's season is also yet another reminder not to lose your mind over a small sample of work. Allen has been one of the best relief pitchers in baseball over the last two and a half years. Two bad games didn't change that.