Rivera's ERA Smokes!

Baseball-Reference has a stat called adjusted ERA+, which is a park-adjusted measure of a pitcher's ERA compared to the league average for those years. In its current career all-time list, for those with 1000+ innings pitched, Pedro Martinez is the runaway leader, with a ERA+ score of 158 58% better than the league average), with old-timers Lefty Grove and Walter Johnson 2nd and 3rd with 148 and 147. But I just happen to notice reliever extraordinaire Mariano Rivera's score: an incredible 198 (!) for his career with 990 1/3 innings pitched, just about to qualify for the 1000+ IP list. The 198 means that Rivera has averaged an ERA almost twice as low as the league average for his career (His career ERA stands at 2.30; the league average for those years has been 4.54). Super Mariano indeed!

Another top-notch closer with an impressive career ERA is Billy Wagner, with 2.38. His league average has been 4.32, for a very impressive 181 ERA+ score, but with only 805 IP at age 36, he may not reach the 1000 IP thresheld before retirement.