(Frank Franklin II - AP) Jordan Zimmermann took the mound yesterday, as he always does, wanting “to do better than the guy before,” he said. He had a problem. Zimmermann pitches after Gio Gonzalez, who for the third consecutive start allowed no runs. And Gonzalez pitches after Stephen Strasburg, who has not allowed a home run in 56 innings. And Strasburg pitches after Ross Detwiler, who owns the lowest ERA among starting pitchers in the majors.

The Nationals’ rotation has become difficult to place into perspective, producing layer upon layer of absurdity. Yesterday, Zimmermann allowed one run in six innings, allowing four hits, walking none and striking out six. It was a stellar performance. It was also, using Bill James’ Game Score as a guide, just the 12th best start, out of 18, by the Nationals this season.

As pitching coach Steve McCatty has said, “they raise the standard for each other.” They can only compete with one another. It may be only 18 games into the season, still an awfully small sample, but the Nationals have outdistanced every other rotation by leagues. Here’s a sampling of the evidence:

>>> Every single one of the Nationals starters ranks among the top 22 in the majors in FIP, or Fielding Independent Pitching, which is a metric that attempts to gauge what a pitcher’s ERA would be regardless of defense. (Full explanation here.)

FIP

Gio Gonzalez 1.51, 2nd

Stephen Strasburg 1.72, 6th

Edwin Jackson 2.11, 11th

Jordan Zimmermann, 2.53, 21st

Ross Detwiler, 2.59, 22nd

(Greg Fiume - GETTY IMAGES) >>> If not for Jackson’s five-run sixth inning in his last start, the Nationals could have a similar ERA ranking. As it stands, they have four of the top 15 ERAs in the majors:

ERA

Detwiler 0.56, 1st

Strasburg 1.08, 6th

Zimmermann, 1.33, 11th

Gonzalez, 1.52, 15th

Jackson, 4.25, 89th

>>> No Nationals starter has a WHIP higher than 0.94; they have all allowed fewer than one base runner per inning, and they all rank in the top 22 in baseball.

WHIP

Zimmermann, 0.70, 5th

Jackson, 0.84, 11th

Gonzalez, 0.85, 12nd

Strasburg, 0.92, 16th

Detwiler, 0.94, 22nd

>>> Collectively, the Nationals’ rotation ranks first in five significant categories – ERA, FIP, Wins Above Replacement, strikeout-to-walk ratio and WHIP – and in most it is not even close. Here are those figures, with the second place team added for context:

ERA: 1.71 (2.48, Cardinals, is second)

FIP: 2.07 (3.05, Phillies, is second)

WAR: 3.8 (3.2, Rangers, is second)

K/BB: 4.68 (3.92, Phillies, is second)

WHIP: 0.84 (1.01, White Sox, is second)

>>> They almost always single-handedly (not to undersell their defense) give the Nationals a chance to win. In seven of 18 games, the Nationals’ starter has allowed zero runs. In 14 of 18, the Nationals’ starter has allowed one or zero earned runs.

>>> This is maybe the most overlooked, most important figure of all. Every Nationals starter is 28 or younger. Only Jackson is older than 26. Jackson will be a free agent after this season, but Zimmermann, Detwiler, Strasburg and Gonzalez have between three and six more seasons of team control beyond this year. They are young and good, and they will be together for a long time.