This is going to be a bit long. Before we can even talk about whether his current babip is high or low we need to see if he has had any change in quality of contact and batted ball type from the last two years to this year. One sizable difference is that his LD% is way down, roughly 7%. Line drives are the balls most likely to be hits and therefore carry the highest babip. GB% is roughly the same, 1% difference is just statistical noise.FB% is up nearly 8%, fly balls are the least likely to end up as hits and carry the lowest babip. His HR/FB% is right in line with what he's done the last couple years so nothing noticeably different there. Now to look at quality of contact. Santana is giving up roughly 5% lower HARD% and giving up about 5% more SOFT% which means that overall guys aren't putting as much good contact in play off him. So what we know is that He's giving up fewer LDs, more FB and inducing weaker contact than he has in past years. All of this should lead to a lower babip than normal for him; the last two years he's carried a .285babip so if he was carrying something in the .230 or .240s we could probably say that it was legit because of the weaker contact he's inducing, but .136 is just unheard of. For comparison sake the lowest babip in 2016 was Marco Estrada at .234, again we're miles away from Ervin's unprecedented .136babip.
Another statistical outlier for Ervin is his 91.5LOB% or strand rate. Most pitchers will carry a strand rate in the 70-75% area on average with some outliers like Greinke who carries it higher towards 80%. Last year the highest strand rate in the majors for starters with enough innings to qualify was Jon Lester at 84.9% nearly 7% short of current Ervin. Overall it's odd, because when you look at Ervin's K/9, which is down, and BB/9, which is up , along with his SIERA, this is perhaps the worst year of Ervin's career according to his peripherals. His velocity is basically the same, his pitch usage is basically the same too and there doesn't appear to be a new pitch. Sorry to say it guys but this all comes down to is that Ervin has been crazy lucky against the probability gods. Sure he's inducing weaker contact so he should be a bit improved from last year, but nowhere near this much and there's no velocity or pitch or pitch usage that can explain any of it.