The Mariners' historic run prevention

On Aug. 7, Jeff Sullivan wrote on FanGraphs:

(S)ince the last day of May, the Mariners have played 59 games, or 36% of a full season. Over those 59 games, the Mariners as a team have allowed 159 runs, with a 2.50 ERA. Because I feel like you aren’t appreciating that, over more than a third of a full season, the Mariners as a team have posted a 2.50 ERA. ... Clayton Kershaw has a career 2.52 ERA. For 59 games, basically, the Mariners have been preventing runs as if every game was nine innings of Clayton Kershaw.

Since that same date, the Mariners’ runs-allowed total is 46 runs better than the American League’s next-lowest runs-allowed total. The Mariners have allowed, over the span, fewer than half as many runs as the Rangers. And yet the Mariners’ record over the stretch is just fifth-best in the AL, behind the Orioles, A’s, Angels, and Royals. As the Mariners have had maybe the best run-prevention streak in franchise history, they’ve lost considerable ground in their own division. And this is because, since the last day of May, the Mariners are also tied for last in the AL in runs scored.

That more or less captures the essence of the team. But let’s step back now to look at the whole year, instead of just the last 2+ months. The Mariners’ team 79 ERA- is the best in baseball by five points. Since the mound was lowered before 1969, only six teams have finished with a lower ERA-, the 1993 Braves leading the way at 75.

Since Jeff wrote that, the Mariners took three of four from the White Sox, allowing eight runs in the four games. The loss was a 2-1 defeat, the winning run scoring after a two-out error in the 10th inning.

The Mariners now lead the majors with a 2.99 ERA -- they would be the first team since the 1989 Dodgers to post a sub-3.00 ERA and the first American League team do so since the 1981 Yankees and the first AL team to do so in a full season since the 1974 A's. They lead the majors in fewest runs allowed per game at 3.25, a figure lower than the 3.27 runs per game the 2011 Phillies allowed, and that staff featured Roy Halladay, Cliff Lee, Cole Hamels and Roy Oswalt.

Jeff used ERA-, which adjusts for league and park. The Mariners' figure entering Monday is still at 79, meaning it's 21 percent better than league average. The best figures since 1969, not surprisingly led by several of those late '90s/early 2000s Braves teams:

1993 Braves: 75 (3.14 ERA)

1997 Braves: 76 (3.18 ERA)

2002 Braves: 77 (3.13 ERA)

1998 Braves: 78 (3.25 ERA)

1985 Blue Jays: 78 (3.31 ERA)

2003 Dodgers: 78 (3.16 ERA)

1969 Orioles: 79 (2.83 ERA)

2011 Phillies: 79 (3.02 ERA)

2014 Mariners: 79 (2.99 ERA)

Six of those other eight teams won 100-plus games. The Blue Jays won 99. Only the Dodgers missed the playoffs after winning 85 games (they finished last in the NL in runs scored). The Mariners aren't last in the AL in runs scored, but they are next-to-last, thus their current position in the standings that leaves them 1.5 games behind the Royals for the second wild card.

The key to Seattle's run prevention has been Cy Young favorite Felix Hernandez (1.97 ERA), a very good Hisashi Iwakuma (2.86 ERA), a surprisingly solid Chris Young (3.27 ERA) and a terrific bullpen that is second in the majors with a 2.34 ERA, just behind the Padres' 2.32 mark.

The Mariners leads the majors with 52 games allowing two runs or fewer -- the Nationals are next at 49. Seattle is only 39-13 in those games, however, a .750 winning percentage. The major league average winning percentage in those games is .851; Seattle is five games worse than average when allowing two runs or fewer. As Mariners fans aren't surprised to learn.

What's amazing is that the fourth and fifth spots in the rotation haven't been that great. Roenis Elias has a mediocre 4.14 ERA and the fifth spot has been filled by several pitches. James Paxton has been the best but he's made just four starts. Erasmo Ramirez has a 4.06 ERA in 13 starts and Brandon Maurer, now excelling in relief, had a 7.52 ERA in seven outings. You don't need a perfect staff to have a great staff, although helps to have King Felix leading the way.

Anyway, it would seem unlikely the Mariners will finish with a sub-3.00 ERA. Their peripherals don't indicate a staff that dominant, but again some of the bad starters have been weeded out, so who knows. Hernandez has to have a bad game one of these times, no? And because the bullpen has been so great, the Mariners have yet to allow 10 runs in a game. (According to the Baseball-Reference Play Index and Twitter follower James Smyth, only three teams have done that for an entire season: the 1909 Cubs, 1918 Senators and 1981 Giants, and 1981 was a shortened season.)

That's nice. But a playoff appearance would be nicer.