With the help of our friend http://www.baseball-reference.com, I went through every game that Mark Prior allowed four or more runs in during his career. Twenty four times in his career with Chicago, Mark Prior allowed at least four runs. After allowing the fourth run, here are his numbers. 42.2IP 41H 22R 49K 25BB 3HBP 4.69 ERA 1.61 WHIP Looking at those stats, everything looks completely normal except for the walks. That shouldn't be a surprise though, because if a good pitcher allows four or more runs, something is off. In Prior's case, it looks like more often than not it was lack of control. So apparently, during his career, after allowing his fourth run, his ERA was just over 4.00. Makes sense, right? Notes: His career ERA is 3.51. His career k/9 is 10.37. After allowing his fourth run, he averaged 10.35. There were 24 games in which he allowed 4+ runs. On 11 occasions, that fourth run scored on a home run. At the end of 2003, his ERA after allowing 4+ runs was 3.88. After 2004, it was 3.84. Before the injuries kicked in, he seems to have rebounded quite well after allowing his fourth run. Someone who is smarter than I am (I'll get out my Meph pager) can go through these numbers and pull more meaning out of them. Obviously we don't know how other pitchers fared in games that they allowed 4+ runs in, so I'm not sure what this all means. The 4.69 ERA would have placed him 32nd in the NL last year. I'm not sure what ERA tells you though 42.2 innings, but if there are 16 teams in the National League, and each has five starters, that equals 80 pitchers. So after 4+ runs, he falls somewhere in the middle of the pack. The 3.84 ERA he had after 2004 would have been 15th in the NL (right behind Ted Lilly). Until the injuries set in, it looks like he was really good after allowing his fourth run. In 2005 and 2006 he wasn't nearly as good. In 2005, however, there were only three instances of 4+ runs and the numbers are skewed by a game against the Astros that he allowed three runs in 1/3 of an inning. He only pitched 4 2/3 innings in 2005, and three of the five runs he surrendered came in 1/3 of an inning.