Felix Hernandez has been the picture of consistency for the Seattle Mariners. He’s made at least 30 starts in every season since 2006 and his only DL trip resulted from an ankle injury suffered in 2008. In the last five seasons, his xFIP- has ranged from 67 to 78. His contract, which calls for him to earn $25 million a year through the 2019 season with a team option for 2020, is looking like a bargain.

It’s easy to forget that the Mariners ace won’t turn 28 until April but he’s already compiled 41.2 fWAR. Here’s a look at how that stacks up with other pitchers their age-27 season. Going back to 1974, here’s the five best pitchers through age-27.

Pitcher IP K% BB% fWAR
Dwight Gooden 1919.2 21.5 7.3 46.9
Roger Clemens 1513.0 23.1 6.9 46.8
Felix Hernandez 1824.2 22.7 7.0 41.2
Pedro Martinez 1359.1 28.0 7.5 40.4
Bret Saberhagen 1660.1 16.3 4.9 39.8

Impressive. Of course it’s not all gravy on the list. Pedro and Clemens enjoyed several dominant years after their age-27 season, but Gooden produced just 8.3 fWAR after his age-27 season, and Saberhagen only had one more strong year.  However, there are good reasons to think that King Felix will age more like Clemens or Martinez than like Gooden or Saberhagen.

First of all, Felix has avoided the disabled list. Past DL time is most predictive of future DL time, and his only stint was an ankle injury. While his innings were limited towards the end of the year due to an oblique strain, he hasn’t had any arm issues. Gooden and Saberhagen both suffered shoulder injuries that sent them to the DL in their younger years, and these issues plagued them later in their careers.

Unlike Gooden and Saberhagen who struggled to compensate for decreased fastball velocity, Hernandez’ velocity losses haven’t hurt his ability to miss bats. He doesn’t reach the upper 90s or triple digits like he used to, but that doesn’t mean hitters have figured him out.

Year FBv SwStr%
2007 95.6 9.8
2008 94.6 8.8
2009 94.0 10.6
2010 94.1 9.9
2011 93.3 8.8
2012 92.1 10.6
2013 91.9 10.7

He’s compensated for diminishing fastball velocity by adding more movement. As his four-seamer has slowed down, he’s throwing more two-seam fastballs, and the pitch has produced an excellent groundball rate. The fact that Hernandez can be just as successful without a dominant fastball bodes well for the latter years of his contract.

A big reason why Hernandez has been successful is the improvement and increasing reliance on his changeup, which is one of the best in the game. In 2013, he utilized the change more frequently than in any other year.

Year CH% Whiff%
2007 9.9 14.8
2008 13.3 13.6
2009 13.6 15.7
2010 15.3 21.1
2011 21.5 16.1
2012 18.0 15.7
2013 23.0 14.3

Coincidence or not, Hernandez posted career-best strikeout and walk rates in 2013. When batters do put the change in play, it has a 60 percent groundball rate. Not only is the changeup a devastating pitch for Hernandez, it’s one of the easiest pitches on the arm. Of the top ten pitchers in innings pitched since 2007, Dan Haren is the only hurler does not throw a changeup on at least 13 percent of their pitches. His curveball and slider are excellent pitches as well, but the development of the changeup separates him from other very good pitchers whose reliance on a breaking ball has taken a toll on their arm.

Felix has always had dominant stuff, but the development of his secondary pitches and his improved command are good indicators of future excellence, even as he ages. The careers of Gooden and Saberhagen demonstrate that past greatness doesn’t always translate into future greatness. However, nearly all signs point to more great years of King Felix. The only red flag, his decreasing fastball velocity, hasn’t resulted in any decline yet.

Finally, here’s the five year Oliver projection for Hernandez.

Season K/9 BB/9 fWAR
2014 8.8 2.1 5.9
2015 8.9 2.1 5.9
2016 8.9 2.1 5.8
2017 8.9 2.0 5.8
2018 8.9 2.0 5.6

Sure, asking even the best projection to look five years into the future is a tall task. These numbers have to be taken with a grain of salt, but it’s a more encouraging outlook than that of other ace pitchers. King Felix just might be wearing his crown for years to come.