"To further emphasize how well Jax pitched, here are Jax's standard and Statcast numbers from his first two postseason appearances:
Seven Total Batters Faced (TBF), .143 BA, two strikeouts, zero walks, zero home runs given up
.298 xBA, 29% K%, 80% HardHit%, 95 MPH average EV, -10 average LA, 145 ft distance (average distance of balls put in play off Jax), 108 MPH MAX EV, 394 ft MAX Distance"
That is a terrific line, but it also serves to emphasize the both low bar and the extreme difficulties relief pitchers face. First of all, if Jax were a starter, and he retired the first seven batters of the game in overpowering fashion, we would praise him, but not overly so because two or three scoreless innings happen all the time at the beginning of a game. We also simply expect (and should expect) starting pitchers to give up a couple of runs here or there so we don't get excited about it when it happens.
In a relief situation, fans sometimes regard an occasional run surrendered (see Duran Jhoan) as being excessive and a sure sign that the reliever has lost it. It also produces wild fluctuations in ERA because of the limited innings pitched. In Jax's case, he had two periods (May and August) when he was pretty bad, but other periods (June!) when he was seemingly untouchable. In addition, any run given up by a reliever in the playoffs gets pretty extreme reactions. Perception of relief pitchers is pretty weird. It's probably not fair, but it's reality.
In Jax's case, his overall body of work looks pretty solid this season. I'm just hoping he's in one of those periods like he was in June. That will come in very handy during the playoffs.