clock menu more-arrow no yes mobile

Filed under:

Yonny Hernandez

Will he establish himself in the Majors?

Yonny Hernandez swings his bat.
Yonny Hernandez swings his bat.
Photo by Christian Petersen/Getty Images

Mosquito is his nickname.

His nickname is on target for the following reasons:

“He’s a throwback to the days when your middle infielders were small, fast, light hitting guys who played slick defense and bunted and hit behind runners and all that.” — Adam Morris of SB Nation

“If he does that [gets on base], man, he creates a lot of havoc.” — Chris Woodward, Manager of Rangers

“He’s just a pest.” — Chris Woodward, Manager of Rangers

His swinging strike rate is awesome.

Let’s start with a benchmark. Last season the average swinging strike rate in the Majors was 11.3%. For last season, Yonny Hernandez’s swinging strike rate:

  • 5.2% AAA 2021
  • 5.1% Majors 2021

His 5.1% swinging strike rate was the 15th lowest in the Majors for batters with at least 100 PAs (per FanGraphs). This is his special skill.

“[Yonny Hernandez] has still shown the plate discipline and selectiveness that we think down the road can lead to productive offensive play.” — Mike Fitzgerald, Assistant GM for Diamondbacks

Type of pitches made a difference.

The following table shows Yonny Hernandez’s performance in 7 day intervals for 2021. Based on wOBA, he had three great weeks, three middle weeks, and three poor weeks. Although they may or may not be related, it suggests that when the percentage of curves and non-sinker fastballs was lower, his wOBA was higher. As Yonny Hernandez gains experience with Major League pitches and applies his strong plate discipline and selectiveness, the type of pitch will have a smaller impact.

Yonny Hernandez, 2021 season. Data from Baseball Savant.

A swing-for-the-fences Diamondback trade.

Years ago I concluded that Mike Hazen favors trades to acquire a player who is near Majors ready, who followed initial success with a slump, at the cost of a prospect who may have a higher ceiling but includes risk because he is years away from the Majors. Perhaps the idea is that the acquired player is an adjustment or two away from becoming an established Major League player, which is worth a lot.

When the Diamondbacks acquired Yonny Hernandez, it was that kind of trade. Hernandez is 24 years old and last season made his debut in the Majors. His defense was great (we’ll cover that next) and his on-base skill was impressive. His three worst weeks were in September, which is a slump. Maybe he is an adjustment away from a batting breakout that will establishing himself in the Majors. The Diamondbacks gave up 19 year old Espinal. In 2020, MLB com ranked him as the 26th best Diamondback prospect. They wrote three things that indicated a high ceiling: “top-flight athleticism,” “plus speed,” and “projecting as a plus defender” in center field.

In summary, acquiring Yonny Hernandez was a swing-for-the-fences trade!

His defense was more than solid.

Yonny Hernandez has a solid defensive reputation per Mike Fitzgerald. My view is that last season’s Defensive Runs Saved (DRS) and Outs Above Average (OAA) show his defense was more than solid. In addition, his versatility to play second base and shortstop, in addition to third base is valuable. His defensive measures for last season follow:

  • 242 innings at third base: +4 DRS and negative 1 OAA.
  • 73 innings at second base: +2 DRS and +1 OAA.
  • 39 Innings at short stop: +2 DRS and +1 OAA.

He learned from his on-field mistakes without being rattled.

“Yonny also was the recipient of criticism from Chris Woodward for mental mistakes in 2021, both on the basepaths and at the plate, which isn’t the sort of thing that you want to have happen as a fringe guy battling for a bench role.” — Adam Morris of SB Nation

There is no substitute for preparation. Nevertheless, execution mistakes happen.

After being called out for making a mistake, sometimes it’s difficult to quickly move forward with confidence. My experience is that several different emotions can accompany making a mistake. If I was a professional baseball player, how might I respond to a mistake? Two thoughts:

  • Quickly label each emotion and put them aside during the game. Deal with them later.
  • Accept that moving forward in my baseball career is an unimaginable string of mistakes to correct/overcome, and use that positive energy to play my best during the game.

His base-running is strong.

His 26.8 feet per second sprint speed is about average in the Majors. Don’t tell Yonny Hernandez because on the base-paths he believes he is a speedster. My view is that it’s often true that believing you have achieved your goal makes achieving that goal easier. Personally, I believe that I write baseball articles delightfully different than any articles ever written.

“But Hernandez plays as if he has the speed, and he couples that with fundamentally sound base-running.” — Chris Halicke

“We’ve talked about applying pressure in every way possible, especially on the bases... He does all his homework, and he’s got the fearlessness to go with it.” — Chris Woodward, Manager of Rangers

“When Billy gets on base, everyone in the world knows that he’s probably going to steal. It’s the same with Yonny.” — Chris Woodward, Manager of Rangers


Yonny Hernandez will likely establish himself in the Majors because:

  • Awesome swinging strike rate.
  • Strong plate discipline and selectivity.
  • Defense is more than solid at third base, with versatility to play second base and shortstop.
  • His baserunning is strong.