Search when does ERA become meaningful on the internet and you'll find tons of studies. It takes roughly 500 IP for ERA to actually mean something, it never reaches it in a single year much less a 40 IP sample. It also never truly becomes meaningful because after 500 IP you aren't the same pitcher you used to be. It is not a stat that tells how good a pitcher is. To give you a super easy example of using 40 IP. You take two pitchers who both are exactly as skilled as each other, each throws 39 1/3 innings with 15 ER. They both load the bases with 2 outs and are removed from the game. Pitcher A's RP gives up a grand slam HR, pitcher B's RP strikes the guy out. For the season Pitcher A has an ERA of 4.05 ERA, pitcher B has a 3.38. Without either of them actually doing anything at all differently one of them ends the season with an ERA 0.66 higher than the other. You may say that is an extreme case but stranded runners like this makes a huge difference for pitchers every year as does BABIP, variance in personal LOB, when they happen to give up HR, quality of opponent faced etc. Looking at Houser more closely what you see is once he breaks 50 pitches he starts to give up a ton of HR's and that seems to be the biggest issue. I don't know if that is something fixable, just a small sample, a problem with his pitch mix etc. The samples are probably too small to judge that from stats, it is more of a scouting thing. It probably comes down to whether or not he can develop a 3rd pitch that is a positive. Right now he is fastball/sinker and everything else was negative in value. Those samples are really small to try to judge with as well.