Checking in on Arnaldo Hernandez

Arnaldo Hernandez is someone who caught my eye when I saw him pitch on June 29 against the San Antonio Missions.  It was his first AA start and I was excited to get a look at him as I had heard he was a decent arm.  I posted in my group chat with RFR that he is a guy who is legit.  Hernandez is also a guy that is eligible for the Rule 5 draft this December.  After watching that start, I believe that Hernandez is a guy that would be a prime target to be selected in the Rule 5.


Let’s take a look at his stuff before we go into more detail about his career and what the future looks like for him.  Hernandez throws a 4-seam and 2-seam fastball, a curve, and a change.  Scouting reports had his fastball 90-94.  In the start I watched, I had him up to 96 with his 4-seam and the range he was working was 92-96.  The 2-seam was coming in at 91-93 and had some arm side run.  As you can see on the videos below, he has the ability to spot his fastball to both sides of the plate.  On the left is the fast ball away.  On the right is the fast ball in.

The change (video below) is deceptive and has good arm side movement with sink.  It is a pitch that will get LHHs out.


The Change Up away to a LHH who can’t stay back and rolls over.

The curve (video below) had depth and produced check swings and a few swings and misses.  It had tight spin and was tough to pick up. Fangraphs put a 50 on his change up and I would say that his curveball has at least the same grade.  


The curve.  As you see, the hitter had a hard time picking this pitch up.  The pitch came out low but Hernandez can and does throw this for strikes.  

Hernandez has actually spent more time in AAA than AA as he filled in last year for two starts in Omaha and has done the same this year.  Hernandez has made three starts for the Northwest Arkansas Naturals this year and selfishly, I’m hoping he comes back to the Naturals so I can get another look at him.  

I don’t know how many innings Hernandez threw last year in extended spring training, but his career high officially is 82.0 innings back in 2015 when he pitched in the DSL, Arizona, and Idaho Falls.  His first year in the organization was 2014 which he spent in the DSL throwing a total of 17.2 innings.  In 2016, Hernandez threw 70.2 innings at Idaho Falls starting 14 games.  Last year he started in extended spring before joining the Legends on June 1.  He threw 57.0 innings there before adding 10.1 in Omaha to finish the season.  All that to say that this year Hernandez has already thrown a new career high of 96.2 innings.  This is almost already 20% more that the previous career high and approximately 30% more than last year.  This leads me to believe that the Royals will have an innings cap on him.

Now I should mention that some of the innings issues have been brought on to Hernandez by himself.  Hernandez received a 50-game suspension for a positive methamphetamine test during the off season between 2016 and 2017.  That suspension was carried out starting the first day of games for the 2017 Lexington Legends.  If he doesn’t have that suspension, Hernandez probably throws 100 to 120 innings last year and can extend out further this year.  Hernandez is a guy that probably needs to go to the Arizona Fall League to showcase his abilities.  He is what that league was created for.  A high talent guy with good stuff who needs to face the highest level of competition before going to the majors.  Of course, again, the problem is what is his inning cap and does he get to go to the AFL because of that inning cap?


Hernandez is not necessarily a strikeout pitcher, but he does get his fair share of them averaging 8.3 per 9 innings pitched across his career.  That number has dropped to 6.4 in Omaha.  However, it was lower last year at Omaha coming in at 5.2 and is currently 7.2.  At NWA this year, he is averaging 8.8 K/9 which is much higher.  Hernandez has good control averaging only 2.1 walks per 9 innings pitched over his career.  At Omaha this year it is 3.9 BB/9 which is almost twice his career average.  I expect that number to get better as Hernandez adjusts to the level.  Hernandez has a 12% Swinging Strike Rate from opponents at NWA this year and it drops to around 10.5% in Omaha.  The SwS% has been about 11% over the last two seasons so this is about current with where he is skill wise.  It is expected that these numbers drop slightly at each level as players move up the ladder so expect his SwS% to be around 10% or slightly higher finishing this year at Omaha.  As guys adjust to levels, these numbers usually go back up slightly so look for some improvement.

Hernandez is more of a fly ball pitcher getting 38% of balls in play hit on the ground this year.  This is slightly better than last year when that rate was only 32%.  At NWA, Hernandez GB% was 43% which is slightly better than his career averages.  Being a fly ball pitcher during the launch angle revolution isn’t the best idea but Hernandez gives up a home run about every 16 innings pitched so he has managed to avoid this.  Hernandez gives up approximately 10 H/9 and only 0.7 HR/9.

Lefties and righties are pretty even against him as far as BA, OBP, and SLG.  Early in his career LHHs had a harder time against him than RHHs.  This year, RHHs have hit for slightly more power against him and have an OPS about .014 points higher.  That’s very even, actually.  RHHs also are striking out 24.25% of the time against Hernandez compared to LHHs who are striking out 18.9% of the time against him.  This would indicate that his curve gets more swings and misses than his change which is true for most pitchers.  

MLB teams usually snag a guy that can stick in their bullpen in the Rule 5 Draft if the team makes a selection.  This year the Royals have Burch Smith and Brad Keller who are Rule 5 guys contributing in a big way.  Both of them started in the pen and have recently moved to the rotation.  As a few contracts expire and there is more room on the roster, the Royals could add some guys this December.  Hernandez has a bright future and may get enough innings if he stays in Omaha for the Royals to get a good read of his abilities against higher level talent without having to send him to the AFL.  I expect the Royals to add him to their roster before the deadline to lock 40-man rosters this November.

13 thoughts on “Checking in on Arnaldo Hernandez

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