Who are some of the most dominant pitches in baseball right now? Depending on the year this question is asked, the answer can bring a host of different names. But one of the few constants has been Los Angeles Dodgers left-hander Clayton Kershaw.

After debuting in 2008 by throwing 107.2 innings and producing a 1.5 fWAR, he's produced an fWAR of at least 4.4 for nine straight seasons, with a streak of three consecutive years above 7.1 mixed in there (2013-15). Since winning his first of three National League Cy Young awards in 2011, the southpaw has finished outside the top three in voting just once. That was a fifth-place finish in 2016 -- mostly because a back injury limited him to 149 innings (21 starts).

With only 10 years in the big leagues, he's already proven to be one of this generation's most dominant hurlers and would have more than a solid case to reach the Hall of Fame if his career ended today. And while his 2017 campaign was on par with just about everything he's done in recent memory -- it's hard to finish third in Cy Young voting without being dominant -- there were a couple instances when he proved to be a mere mortal.

Still Really Freakin' Good

Let's not get it twisted, though, guys. We're not saying Clayton Kershaw isn't good anymore. Say what you want about his postseason track record, but anyone who tries to make that same argument about his regular season performance will have a hard time being successful.

As just mentioned, he was a finalist for NL Cy Young honors for the sixth time in seven seasons this past year, and as usual, the numbers are rather impressive. The 4.6 fWAR he produced was actually his lowest in a single season since 2009 (4.4), but that also shows just how good he's been for such a prolonged period of time.

Kershaw did hit the disabled list, which limited him to 175 innings of work (27 starts). Despite that, the lefty still posted an 18-4 record with a 2.31 ERA, a 29.8% strikeout rate, and a 4.4% walk rate. All of these numbers led to a 3.04 SIERA, and they probably would've been better if he wasn't so prone to the home run.

Since 2009, the veteran never saw his homers-per-nine-innings rate climb above 0.63, but he just about doubled that this year with a 1.18 mark. There are plenty of discussions as to why it happened -- Kershaw wasn't the only one to have this problem -- but still, it's noteworthy that the Dodgers' ace was his usual dominant self outside of giving up more homers than ever.

Struggles Against Lefties

Facing Kershaw in any kind of situation seems like a nightmare for opposing hitters, especially for left-handers.

Once the southpaw started winning Cy Youngs while making annual trips to the All-Star game, left-handed hitters have had a tough time getting anything done against him. Since 2011, they've never posted a wOBA higher than .255 when facing L.A.'s top arm, including a .137 mark in 2016. But this past year, they managed a .308 wOBA.

Yes, the 7 homers they hit off him is the most he's allowed since 2010, but his batted-ball profile looks much different than it has recently. The below table shows how his line-drive rate (LD%), ground-ball rate (GB%), fly-ball rate (FB%), and hard-hit rate (Hard%) against lefties compare against one another since 2014.

After limiting hard contact at a career-low rate in 2014, the rest of Kershaw's above batted-ball numbers were trending in the direction we'd want to see, making it no surprise as to why he was so dominant. But everything went in the wrong direction this past year, and his hard-hit rate allowed settled in over 30.0% for the first time since 2013.

He also had a hard time putting hitters away, as his 25.7% strikeout rate in this situation was the lowest it's ever been, while his 3.6% walk rate was the highest it's been since 2013.

Trouble With Secondary Pitches

Kershaw brings a fastball that he can run up to the mid-90s when he needs to, but a huge reason behind his greatness lies in the effectiveness his secondary pitches. His curveball gets all the attention, but it's only the third most-used pitch in his arsenal, with his fastball and slider consistently outpacing it.

To show how important both his slider and curveball are, the below table gives us a year-by-year look at the wRC+ opposing hitters have mustered against these offerings since 2009.

First of all, this is just disgusting. The fact that his curveball produced a negative wRC+ for five consecutive years heading into 2017 should be a crime.

The other thing worth noting is that the last time hitters were in the black with regard to wRC+ on both these offerings came all the way back in 2011. And judging from how low those numbers were, it's easy to see that this is the best Kershaw's opposition has collectively fared against his secondary stuff.

Moving Forward

As we've mentioned throughout, it's not like these numbers are necessarily bad. Kershaw is still an incredible pitcher, but he showed signs of being human a little more in 2017 than we've seen in recent memory. While his 2.31 ERA led all qualified NL starting pitchers by a significant margin, it was actually the highest it's been since 2012 (2.53). The same could be said about his 3.04 SIERA, which hadn't climbed over 3.00 since that same 2012 campaign (3.31).

Is Kershaw going to be any less dominant on the mound in 2018? There isn't any real data telling us otherwise, so he'll probably be the same ol' stud we've grown accustomed to watching. These small trends are worth pointing out, though, because they've deviated so much from other recent performances (even if a "down" performance for him is still pretty good).

Maybe these numbers are just a blip in the radar. Or maybe it's small things like this that will start happening for a pitcher entering 2018 as a 30-year-old with recurring back problems and 1,935 regular-season innings under his belt.

We'll find out soon enough, but one thing is for certain -- these "struggles" and human-like moments should help us appreciate just how great he's been throughout his career.