TL;DR version: He has an unparalleled ERA in a very small sample size.
I sometimes find myself bouncing around on Baseball Reference for hours at a time, like a procrastinating student on Wikipedia. In the most recent of these sessions I wound up on Mike Adams' page and realized he was even more dominant while he was with the Padres than I had recalled. I remembered he had a couple great seasons, but it somehow slipped my mind that he was lights out year-in and year-out, with nary a bad one in the bunch. In three seasons and most of a fourth with San Diego, Adams recorded a 1.66 ERA in 217 innings. I figured that had to be a franchise record for anyone with at least 200 innings, so I ran that query through the B-R Play index and sure enough.
| ERA | IP | Year(s) | |
| Mike Adams | 1.66 | 217 | 2008-11 |
| Kevin Brown | 2.38 | 257 | 1998 |
| Heath Bell | 2.53 | 374 | 2007-11 |
Hey, I was right! It was bound to happen at some point. With my suspicion confirmed, I decided to see how low I had to drop the innings limit before he lost his crown. I slashed the innings minimum by half and there was Adams again, still on the top of the heap.
| ERA | IP | Year(s) | |
| Mike Adams | 1.66 | 217 | 2008-11 |
| Huston Street | 2.03 | 128.2 | 2012-14 |
| Ernesto Frieri | 2.33 | 108.1 | 2009-12 |
Of pitchers matching the 100-inning criteria, Nick Vincent is the highest ranking current player; his 2.48 ERA in 120 innings the past three seasons ranks sixth. When I dropped the innings limit to 50, Vincent fell to eighth and another current Padres pitcher came out of nowhere and shot to the top of the list.
| ERA | IP | Year(s) | |
| Joaquin Benoit | 1.58 | 51.1 | 2014 |
| Mike Adams | 1.66 | 217 | 2008-11 |
| Huston Street | 2.03 | 128.2 | 2012-14 |
From there, I kept making the sample size smaller and smaller, shaving off 10 innings at a time. Benoit was still the all-time leader at the 40, 30, and 20-inning marks; it wasn't until I got down to 10 innings that Benoit fell to second. In his three appearances with the big club this season, Jason Lane allowed one run in 10.1 innings for an ERA of 0.87.
Benoit is expected to return in about 10 days and be active for the last couple weeks of the season, and is under contract for next season, so his ERA is still a very fluid thing. It remains to be seen if he'll hold steady and keep his top spot as he reaches new innings milestones. I'll let you know where he stands when (if) he gets to 100 innings.