Andrew Knizner Should Swing Less

How About Andrew Knizner? The backup catcher has caught fire in the second half and has people clamoring for him to play over Yadier Molina. This is the same player who was worth -1.3 fWAR in his career prior to this year and the same player who many had already given up on.

Now I’m not trying to call anyone out here. I didn’t have much faith in him prior to this hot streak either. It’s just been surprising to see Knizner turn his season around so quickly.

Still, I have a hard time believing that someone who was so bad has somehow flipped a switch and become good. Regardless, I’ll let my optimistic side take over and take a look at this hot streak.

His 147 wRC+ in the second half is obviously not sustainable. If I tried to tell you it was, I hope you would either stop reading or blow me up in the comments (I know that’s never an issue). Still, we can learn a lot from Knizner’s streak.

What does it tell us about how Knizner can be productive? Let’s find out.

Red Flags

Before I really get into the analysis, I want to point out a few red flags. For starters, Knizner has a .389 BABIP in the second half of the season. That’s about as big of a red flag as you can find for a hitter who’s never shown an ability to sustain high BABIPs.

I’ve seen some people refer to Knizner’s streak as being BABIP-fueled and that’s not wrong. Though, it’s not entirely accurate either, as I’ll demonstrate later.

Part of the high BABIP can be attributed to his hard hit rate has rising above 50% since the All-Star break. Hitting the ball hard makes it more likely that a ball in play will be a hit, so to a degree, the elevated BABIP makes sense.

Knizner doesn’t normally hit the ball hard, though, so that’s another reason to question the sustainability of this streak. He has an average exit velocity of just 86.4 mph this year and an average of 87.3 mph for his career. That’s not exactly slugger material.

He can’t be expected to run a near-.400 BABIP for the rest of his career nor can he be expected to have a 51.4% hard hit rate consistently. So, don’t expect this to be the new normal.

His career ISO is just .077. That’s Victor Robles, Nick Senzel, and Tony Kemp range. Those aren’t names that jump off the page. In fact, of the 32 hitters with ISOs between .070 and .090 this season (min. 100 PAs), just four have been average or better hitters. That’s not exactly great company to keep.

So, this hot streak is great, but it will end at some point because I don’t think Knizner just happened to find power, though it is encouraging to see him hitting the ball harder.

It’s not the batted ball data that I want to focus on, though. Rather, it’s the non-batted ball data. To put it simply, I want to look at his plate discipline because that’s going to be the key for Knizner.

Patience

So, how does a poor hitter find production? He doesn’t look for it, he looks at it. Specifically, he looks at the ball.

If Knizner isn’t going to hit the ball hard, then he’s not going to have great results on contact. The antidote is to walk more. And how do you walk more? By swinging less.

And that’s exactly what Knizner has done over the course of this hot streak. Most people have focused on Knizner’s BABIP as the reason for his success. That is absolutely fair. He’s hitting the ball harder and having better luck and that’s a huge component of any hot streak.

What’s flown under the radar are the changes he’s made in his plate discipline.

Brooks Baseball gives a player’s swing rates by pitch category on a month-to-month basis. Here’s what Knizner’s look like.

This gives a clear view of what’s changed, but I’ll also share the data in tabular form.

Notice how Knizner’s swing rates are at a season low in August for each pitch type. That’s the key. So, it should come as no surprise that he has a 14.3% walk rate in August.

When I saw this, I immediately thought of Justin Choi’s article at Fangraphs earlier this season. The whole premise of his article is that hitters should swing less to counter pitchers who have gotten nastier and are throwing fewer pitches in the zone than ever.

Let’s examine this further. Choi cites Tom Tango in his piece, saying “few hitters accumulate positive run values with their swings.”

That’s because swings generate bad results much more often than good results. The league batting average is .243. That means that hitters tally a hit on 24.3% of their batted balls. So, basically ³⁄₄ of batted balls don’t do anything positive (this is rough math, I’m not taking sac flys and other “productive” outs into account).

It’s even worse for Knizner. He’s batting just .232 and has a .210 career batting average.

But not every swing generates a batted ball. 24.7% of swings are whiffs (21.7% for Knizner). Then there’s foul balls too. That’s a lot of negative results that come from swinging the bat.

Now consider what can happen when a player doesn’t swing the bat.

The pitch is either a ball or a strike. That’s it. This year pitchers are throwing the ball in the zone 41.3% of the time. So, about 60% of the time, when a hitter takes a pitch, it will end well for him.

Home runs and extra base hits change that calculation, but not enough to make the average swing more valuable than the average take.

Don’t believe me? Here’s the proof.

If you look closely at that table, you’ll notice that very few hitters land to the right of 0 on the x-axis. That area to the right is positive run value on swings. The bulk is to the left, which is negative run value on swings. That stands in stark contrast to the run value on takes. Every hitter shown has a positive run value when not swinging.

That’s not to say hitters should never swing. Hitters are still trying to hit the ball and do damage. But hitters who are more capable of doing that should swing more often than hitters who aren’t.

With that premise in mind, let’s look at Knizner individually.

As a reminder, negative run values are bad for the hitter and good for the pitcher. This is pretty typical for hitters, but good hitters can see their swing runs tick positive. There’s a stark difference with Knizner. He’s not just bad when he swings, he’s really bad.

So, with that being said, let’s see how much he swings relative to other hitters and how many pitches in the zone he sees relative to other hitters. (I’ve said it before in my articles, but Baseball Savant and Fangraphs numbers don’t always match up. I’ll list both sites for clarity.)

To be honest with you, I don’t know how something as simple as zone rate can have such a drastic difference. It’s a simple equation - pitches in the strike zone divided by total pitches. Regardless, it’s clear that Knizner sees about a league average number of strikes.

Nothing special there. He also has slightly below average swing rates according to both sites.

Knizner is already a patient hitter. That’s what he should be, but he’s not patient enough.

The encouraging sign is that he has made strides toward being more patient in the last two months.

Obviously, the disclaimer is that he’s had just 35 plate appearances in August and 55 in July. Still, it’s not surprising that he’s had his best results when he’s been the most patient. I don’t want to leave out the importance of hitting the ball hard, but it’s the patience that stands out to me because that’s Knizner’s best path forward.

Let’s use Tony Kemp as an example. VEB’s (former) own Ben Clemens wrote an excellent piece for Fangraphs in February discussing how Tony Kemp excelled in 2021 by not swinging. You can find the article here. It’s absolutely worth reading.

After reading the article, it seems that Tony Kemp is a perfect case study for Knizner and after looking at Baseball Savant, it’s clear that Kemp can be an inspiration for Knizner.

Last year Kemp had a .129 wRC+ despite showing little power. HIs patience at the plate was a huge reason why. Notice how Knizner swings way more than Kemp did last year and notice how their average exit velocities are practically the same.

I would love to see Knizner drop his swing rate close to Kemp’s 42%. If that feels drastic, it’s because it is. But when you’re a player without any semblance of power, you need to walk a lot.

Sure, Kemp had more power, but it was really his walk rate that caused him to be so productive. He also struck out less but Knizner is a player with a below average strikeout rate too.

It’s not a perfect comparison, but Kemp shows how a player can be productive without power.

He also shows how players without power can be unproductive when they get aggressive as Kemp’s wRC+ has dropped to just 80 this season after his swing rate jumped to 49.1%.

That’s an above average swing rate and it caused a diminished 8.4% walk rate. That’s still (barely) above average, but that’s not good enough for a slight hitter with minimal power.

Knizner can look closer to home for another example — Brendan Donovan. Donovan has a 132 wRC+ largely because of an insane 12.2% walk rate. He also has a .087 ISO.

You know what else he has? A swing rate below 40%. Donovan’s 39.5% swing rate is even lower than Kemp’s swing rate was last season and that patience has been a huge reason for his success.

Again, the archetype is clear. Players without power need to walk if they are going to be productive. The less power, the more a player must walk. A 10% walk rate is good, but Knizner needs to walk even more even if he wants to produce.

He needs to be in that 12-13% range at least if he wants to be productive with so little power. His other option is to hit for more power like Kemp or hit more line drives like Donovan.(Earlier in the year, I wrote about the importance of line drive rate for hitters with limited power)

Conclusion

So, where does this leave us? Knizner needs more walks, more power, or more line drives. He’s seen an uptick in all three of these things during his hot streak and that has fueled his 147 wRC+ in the second half.

The recipe is clear. I don’t expect Knizner to suddenly hit for more power. It’s possible if he hits more balls in the air and fewer on the ground, but he’s never been much of a power hitter in the majors. Even so, ticking his ISO above .100 would help.

If Knizner is going to be the same kind of hitter then he needs to leave the bat on his shoulder more often. Take more pitches. Take more walks. Tony Kemp had success with that approach last year and Donovan has had success with an extreme level of patience this year.

Knizner has been more patient in the second half. Is that a sign of things to come or is that just a part of his hot streak? The answer to that question may determine how viable Knizner’s bat will be in the future and it may determine his standing with the St. Louis Cardinals after Yadier Molina is gone.