Seattle Mariners: Defining an ace

Felix of Kuma?

In February, Seattle Mariners starting pitcher, Felix Hernandez, signed a contract extension worth $175 million over the next seven years ($40.5 million in 2013 & 2014, then an additional $134.5 million over the last five years.

He is getting paid like an ace. He has pitched like an ace. He is pitching like an ace. But is he the ace?

The Mariners are in the lucky position to have a second pitcher playing like an ace…Hisashi Iwakuma.

Signed over from Japan before the 2012 season (roughly 1.5 years after the Oakland Athletics won a right’s bidding war but failed to come to terms), Iwakuma is, at a surface glance, out-performing Hernandez through 15 starts this season.

In his first year with the team, Iwakuma went 9-5, with 2 saves and a 3.16 era over 125.1 innings.  A good line considering it was his first time playing in MLB.

However, in 2013, Iwakuma has improved on those numbers going 7-2 in 15 starts, with 100.1ip, 90k, 17bb and a 2.06 era.

Those numbers are slightly better than Hernandez who sits at 8-4 in 15 starts, with 104.2ip, 110k, 20bb and a 2.32 era.

With the success both pitchers are having at the top of the rotation, the real question is, which one is actually the Mariner’s ace?  Before we can answer that, we need to define what an ace actually is.

Defining an ace


Felix Hernandez earns the Ace paycheck. (Photo:

For me, I want my ace to be my most effective workhorse. He needs to be able to pitch late into games to help rest the bullpen.

He needs to pitch more effectively on the road in hostile environments, because that is always a more difficult task than pitching with your own fans behind you.

He needs to pitch well against the teams in the division because that dramatically impacts the standings.

However, even more important, he needs to pitch well against the best teams in the league, because those are the teams he will be seeing in the postseason.

With those qualifiers in mind, let’s take a deeper look at the season so far (15 starts each). We will compare starts where both pitchers have faced the same team.

We will also exclude the importance of wins, because defense, lack of run support and blown bullpen assignments can all alter the outcome of a game.

I want to focus primarily on which pitcher is the true ace of the Mariners…the pitcher most likely to come up big on the road against a good team, down two games in a 7 games series. That is when I want my ace up.

So who is the real ace?

As far as being a workhorse, both pitchers have had the same number of starts (15) and have gone close to the same amount of inning (I:100.1/H:104.2).

Iwakuma has had one more quality start (I:12/H:11), with a QS defined as going at least 6 innings without giving up more than 3 earned runs.

However, 7 of Iwakuma’s 15 starts have been at home, whereas Hernandez has pitched 9 of his 15 starts on the road.

Edge: Even

Pitching on the road is the next qualifier. While Hernandez has had his one more game, also indicated by innings pitched (I:51.2/H:62.0), he has also vastly out-performed Iwakuma.

In one more start and 10+ innings, Hernandez has given up one less hit (I:47/H:46), six less earned runs (I:18/H:12), one less walk (I:14/H:13) and two less home runs (I:8/H:6).

Interesting numbers since Iwakuma is usually considered more of a control pitcher than Hernandez.

Edge: Hernandez

Next up in our defining an ace, is pitching against teams in the division. In this category, Iwakuma actually has two more outings than Hernandez (I:8/H:6).


Hisashi Iwakuma has had Ace like numbers this year. (Photo:

Even with the sample size difference, Iwakuma still clearly has out-pitched Hernandez, mainly because of one horrible outing King Felix had against the Texas Rangers.

But we are not in the business of excluding terrible outings, because a bad outing in game 7 of a World Series will cost the team a championship.

So over those division starts, Iwakuma has pitched 9+ innings more (I:50.2/H:41), while giving up four less hits (I:35/H:39).

He has also only given up two more earned runs (I:12/H:10), and only one more walk (I:8/H:7) and home run (I:4/4H:3).

Edge: Iwakuma

Going into the last qualifier, defining the ace of the Mariners is a dead tie, much as it has been all season.

So, which pitcher is better against the top competition?

Against the two, 1st place AL teams that both pitchers have faced, the numbers are close.

Against the Detroit Tigers (39-30, 1st in the ALC), they both have pitched one game. Hernandez went two more innings (I:6/H:8), gave up 1 less walk (I:1/H:0), and had ten more strikeouts (I:2/H:12).

He did give up one more run (I:0/H1:), but neither pitcher came away from the game with a win.  Close stats, but Hernandez had the more dominating game.

Against the Oakland Athletics (43-30, 1st in the ALW), Hernandez has also pitched better.

Though Hernandez has had one less start against the A’s (I:3/H:2), he has had almost as many total innings (I:18/H:14.2), given up seven less earned runs (I:7/H:0), one less walk (I:3/H:2) and one less home run (I:1/H:0).

He also has nearly as many strikeouts as Iwakuma (I:19/H:16) and a perfect ERA (I:3.50/H:0.00).

Given that it is also against a division opponent, it changes the light that Iwakuma’s edge should be viewed in and amplifies the significance of this qualifier.

Edge: Hernandez

So, while both Mariner pitchers are clearly among the league’s best, the team’s true ace still remains Felix Hernandez

Add in the fact he is still only 27 (compared to Iwakuma at 32), and has remained relatively injury free, King Felix should continue to be the team’s ace for years to come.


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About Jonas Hyde

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