what makes middle relievers unreliable from year to year Lack of talent. Really I think it has a lot to do with discrete components. What I mean is that relivers work at most 1 or 2 innings per outing. Such a small performance sample is unduely influenced by luck, both bad and good. I don't think so. In terms of ERA it is, but for looking at the rate at which a pitcher gets people out. OBP against, stuff like that. I think it's more that there aren't a lot of consistently good middle relievers, and teams too often jump at the flash in the pan or the guy in his early to mid 30s who's right about to go downhill. I think you have a good point. If I were going to judge a reliever I would look at secondary stats like WHIP. I haven't given my "discrete component" theory much thought recently, but I think it is so hard to judge a reliever because we doen't yet have real good metrics. Anyway, giving a 38 year old reliever who was comming off of high IP totals the last two years is a receipe for disaster. I'm look at you Mike Remmlinger.