Best Mariners Rotation Ever? So Far, Yes (Part 2: Rotation ERA/FIP)

About a week ago we took a look at the amount of runs the Mariners have allowed so far this season in comparison to past Mariner rotations.  This year’s rotation is on a pace that no other Mariner team has been on.

In that post I didn’t separate the rotation from the bullpen, but today we will take a closer look at just the rotation.

ERA (Earned run average) is not regarded as the most reliable stat for a number of reasons, most notably the teams fielding.  But since it’s the most well known stat for pitchers, I’ll dive into it a little bit.

The 5 Mariners starters have the following ERA’s:

• Michael Pineda – 2.30
• Felix Hernandez – 3.04
• Doug Fister – 3.24
• Erik Bedard – 3.41
• Jason Vargas 4.50

That gives the rotation a 2.76 ERA total.  There’s a couple of things that are pretty spectacular with these numbers.  First of all, the Seattle Mariners have never had all 5 starters with ERA’s under 4.00.

The 2003 rotation, which is considered by many the best, had two starters over a 4.00 ERA (Freddy Garcia –  4.51 and Gil Meche 4.59).  The 2001 Mariners, the 116 win team, were a little closer.  They had 2 starters over 4.00 (Paul Abbot – 4.25 John Halama – 4.73) but Halama only started half the season.  The 1990 team was the closest of any team, having 3 starters under 4.00 and a 4th starter with an ERA just over 4.03.  They had a variety of 5th starters and a few of them had ERA’s under 4.00.  There wasn’t enough starts by one single person to give him the label as ‘5th starter.’  That rotation had an ERA of 3.67.

Vargas had been under a 4.00 ERA until his last two starts in which he got roughed up a little bit.  I don’t think those starts are anything to worry about, I have a theory but that will be saved for another post, and I bet he’ll be back to himself soon enough.

Simply put, the Mariners’ rotations ERA is set to break a team record, and it’s not even close right now.  This rotation is almost a full run lower than the next lowest in team history.  I’m telling you, these guys are incredible.

If ERA isn’t your stat of choice, then we’ll move on to the next one.  The problem with the newer stats is that it’s harder to compare them to Mariner teams of the past.

Let’s start with ERA+.  The equation for this stat is 100*(lgERA/ERA).  To make it simpler, 100 is average.  Anything above that is good, anything below is bad.  The stat is adjusted for park factors, also.  That makes it a bit more reliable.

The Mariners 5 starters ERA+ is as follows:

• Felix Hernandez – 123
• Jason Vargas – 83
• Doug Fister – 115
• Erik Bedard – 110
• Michael Pineda – 162

There are a few things to clear up.  Michael Pineda’s ERA+ will probably go down some.  This shows just amazing Pineda has been.  Truly, 162 is incredible and close to the top in the league.  To contrast, Jason Vargas’ ERA+ should go up some.  He’s a fly ball pitcher who pitches in a pitcher’s park and therefore stats with adjusted park factors will hurt Vargas.  This doesn’t mean Vargas is a bad pitcher, it means that Jack Z is a smart GM.

This leaves the Mariners rotation with an average ERA+ of 118.6.  The 1990 ERA+ was 110.5.  This is again, excluding the 5th starter since there was no clear 5th guy.  The 2003 rotation had a 111.2 ERA+.  The 2001 rotation was at 121, excluding a few starts by Brett Tomko and Denny Stark.  So, we finally have someone beating this year’s rotation, but just barely.

There’s one more stat to look at that has to do with runs scoring.  That is called xFIP.  This is a stat that takes out a pitchers defense and the park factors.  I don’t buy into it quite as much as other people do, but it’s still useful.  As SSI just pointed out, the Mariners defense has become quite useful in the month of May.  This stat takes away how good or bad the defense could be.  Unfortunately, it’s not nice to ‘pitch to contact’ type of pitch.  On the other hand, those pitchers aren’t usually as good.

Here’s the Mariners rotation xFIP:

• Felix Hernandez – 2.91
• Michael Pineda – 3.19
• Doug Fister – 3.73
• Jason Vargas – 4.31
• Erik Bedard – 3.37

As you can see, there’s still only one guy over 4.00.  With this stat Vargas is closer to that magical 4.00 mark.  Pinedas and Fister’s xFIP are higher than their ERA’s.  Those two haven’t given up many home runs.  Some people call that luck, I say it’s somewhere in between luck and skill.

Still, this stat again shows what we’ve already proved.  These guys are good, really good.

Best Mariners rotation ever?  These stats say yes.

Go M’s!

Andrew