Planning Ahead for MLB Rule Changes

As if 2020 has not brought about enough change, we could be on the cusp of even more. There’s no timetable and no guarantees, but MLB has at least considered making some significant changes going forward. I will be focused on the following three possible changes, their potential impacts, and how teams can plan ahead.

1. “Robot” Umpires

2. Banning the Shift (2 infielders on either side of second base)

3. Moving the mound back two feet

Robot Umpires

Taking away the human element of an umpire is not necessarily something I am in favor of, regardless of how bad they can be at times. Adapt, or die, though. If robot umps become a thing, this will impact pitcher performance, how catchers are valued and to some extent, how hitters perform (and umpire WAR!).

It’s difficult to imagine a world where literally every pitch outside of the strike zone actually ends up as a ball. The implications of this are huge. This post from The Hardball Times includes a run value matrix for converting a ball to a strike (AKA framing) in each count. The creators of this matrix (Brooks and Pavlidis) also developed a weighted context-neutral average of .14 runs per successful frame job.

To paint the picture of how valuable this rule change would be, Zach Davies threw 125 strikes in 2019 that would have been called balls with a robot ump. Multiply 125 by the run value of .14, and the combination of human umps and good catching saved Davies 17.5 runs. Converting those runs to the 2019 runs per win value of 10.296, Davies was worth an additional 1.7 wins than he would be with robot umps. In monetary terms, 1.7 wins was worth approximately $2.89 million in 2019. That’s almost three million reasons why this is a big deal.

Having said that, it’s not completely fair to assume that Davies will give up 17.5 runs more with a robot calling balls and strikes. For starters, he might start trying to throw throwing more strikes. The counts in which previously framed pitches are called strikes would now become balls, which would have a ripple effect (flipped count, throws different pitch, executes/doesn’t execute that pitch so he does/doesn’t throw an additional pitch, etc.). The point: If the pitchers who currently rely on getting those additional called strikes are incapable of throwing more strikes, not only will their walks increase, but hitters will be in more hitting counts to do damage.

The question then becomes: What pitchers rely more on good framing vs. rely on swings out of the zone? Pitchers who rely on deceptive stuff to get swings out of the zone will be more prepared for this rule change than those who rely on their catcher to bail them out on shadow pitches. Trevor Bauer's outing from 9/9/20 is a great example of this...he went 7 and two-thirds with 10 K's, allowing just three hits, no runs and no walks...with a 69% out-of-zone rate.

What pitchers benefit the most from balls getting converted to strikes?

(*Starters minimum 1,000 pitches out of the zone (O-Zone). Run values are based on their total number of called strikes out of the zone, multiplied by .14.)

(*Relievers minimum 300 pitches out of zone (O-Zone). Run values are based on their total number of called strikes out of the zone, multiplied by .14.)

The rankings above are sorted by highest percentage of called strikes on pitches out of the zone that were not swung at. It is important to differentiate what pitchers are intentionally trying to get swings and misses out of the zone, versus those who throw out of the zone and get bailed out by the ump or their catcher. Essentially, the pitchers with the largest gaps in out-of-zone strikes on non-swings compared to the overall number of pitches out of the zone, are the ones who I would expect to continue performing similarly to what you see now. Those with small gaps are the ones who may struggle if robot umps become a thing. I will not get into each pitcher, but the next step I would take here is pulling up Noah Synergaard’s profile and determining 1) does he have the command to throw more strikes if needed, and 2) how does his stuff play in the zone if he has to throw more strikes?

For catchers, the robot umps would have a more drastic effect on their value. Pitch framing becomes completely de-valued. I do think there will always be value in a catcher controlling the pitching staff and providing an internal spike of confidence for a pitcher when he likes throwing to a specific battery-mate who presents a good target and calls a good game, but this will carry less value than ever.

To determine what a catchers value looks like going forward, I started with this methodology, where @mhatter106 breaks down the components of a catcher and created a spectrum. The two biggest pieces of a catcher’s value are his batting (45.4%) and framing ability (31.3%). With the introduction of robot umps, this significantly alters the catcher value spectrum. Below are two tables representing the shift in value following the 2019 season, using the same methodology without the framing aspects. (Minimum 300 PA’s).

Both of these tables are important. The table on the left sort of displays what we know already and the table on the right shows us players that are essentially undervalued right now. If the rule change came tomorrow (in 2019), they are the catchers whose value would shoot up the most overnight.

I then found out that fWAR started including pitch framing in 2019 (WAR = Batting + Base Running + Fielding + Catcher Framing + Replacement Level divided by Runs to Wins), so I created the same charts. (Note: I did not do this for the pitchers because I feel their WAR will be much harder to predict with robot umps than it will be for catchers. Pitchers will either continue pitching like they do, or throw in the zone more, and throwing in the zone more would likely decrease their performance. For catchers, we can just remove the framing component.)

What catchers’ values change the most?

Comparisons using fWAR instead of the spectrum turned up similar results, they are slightly different due to the weighting of each “tool” in the spectrum. It’s also important to note these are all based on 2019. Omar Narvaez, for example, has completely remade himself defensively but is now struggling offensively.

Players and agents will want no part of this, but is it possible to have contingencies in a catcher’s contract depending on whether this rule comes into play? Like I said, there will always be value in calling a game, but pitch framing will be gone and that is worth millions.

Banning the Shift

I am not exactly sure how banning the shift has been defined, but from what I have gathered they will require two infielders to be on either side of second base. The primary purpose for this would be to increase offensive performance, so we need to ask what pitchers will suffer the most and what hitters will benefit?

Here are the starting pitchers that currently benefit the most from the shift, based on their difference in wOBA and xWOBA, minimum 550 batters faced.

The highlighted column shows the pitchers who had the largest differences between their overall actual wOBA and expected wOBA. The “Shift Actual wOBA Difference” column is the difference between actual wOBA when there is a shift on versus when it is not. By banning the shift, these pitchers could see some regression, but keep in mind the shift “%” column, as some pitchers had the shift behind them much more than others.

For good measure, I also found the differences in BABIP and xBABIP, since wOBA takes home runs into account, which the shift cannot control. I created my own version of xBABIP by removing home runs from xBA.

The names that pop up on both lists: Jack Flaherty, Justin Verlander and Yu Darvish. Is it safe to say these pitchers won’t perform as well with no shift? Maybe. The shift was on 84% of the time when Justin Verlander faced left handed hitters. When the shift was on, his actual wOBA against lefties was .253 and his xwOBA against was .359. So I think it’s quite possible. The typical lefty shift against Verlander is below.

What hitters will see their value tick up the most? Here are the top 10 differences in wOBA and xwOBA when the shift is on.

Makes sense that Gallo leads the way here considering he pulls the ball almost 50% of the time. Here is what those shifts look like when he hits.

Here are the differences in BABIP and xBABIP for the same reason as why I did this for the pitchers, wOBA accounts for home runs which cannot be controlled by the shift. These are overall season BABIP numbers, regardless of the shift being on, or not.

This list also needs to be taken with a grain of salt. Should teams trade for Chris Davis? Wouldn't recommend it, not only because of his contract but also because he strikes out 40% of the time. What this tells us is that when he does put the ball in play, he hits into the shift quite often. Dietrich, on the other hand is a player who I would explore acquiring, should teams believe there is a good chance this rule comes into effect. His strikeout rate is up some this season, but he demonstrated in the past that he can be a serviceable player. In the past four seasons (starting with 2016), his shift rates against have gone from 15% to 11% to 22% to 55%. His wRC+ has taken a hit, going from 121 in 2016 and 101, 108 and 102 in the years following. Is it possible his 2020 strikeout rate is up from his career average because he is trying to beat the shift?

Moving the Mound Back

This section will be more based on my assumptions than actual data. I thought about trying to project movement of the additional two feet but have no data to validate whether I am right and physics was never my thing.

The goal of this rule change would be to once again, increase offensive performance. I believe that is likely to occur, but I also think there could be some counter-effects to what MLB is trying to accomplish.

With a longer distance, it’s pretty likely we will see an increase in walk rates (especially if we get robot umps at the same time). Catcher blocking would also become more important. Pitches move a lot over their last two feet, especially breaking balls, and I think pitchers will need some time to make adjustments to the new distance. Hitters will probably start hitting fastballs better because they not only have more time to react, but they also have more time to determine the pitch type and whether or not it is a hittable pitch. For this reason, I believe there will be an even further decrease in fastball usage. We have already seen that this season, but why would pitchers throw the same amount of fastballs if hitters are more incentivized to swing at them to avoid breaking balls with more movement?

Pitchers with strong command of their secondary pitches will be successful, in my opinion. Sliders and curveballs will have an additional two feet to move. The sharper pitches will be easier to command, but picture a Clayton Kershaw or Trevor Bauer curveball that drops five feet, starting even higher in order to end up in the strike zone. This is where teams should be looking at long-form movement over short-form. Long-form movement gives a more accurate depiction of pitch movement, and pitches will have even more drop by moving the mound back two feet.

Summary

While it’s very possible that these rules never actually come to fruition, teams should be at least start considering the impact these changes could have. Especially for a team in rebuilding mode with minimal pressure to win now. Justin Smoak was just DFA’d and Derek Dietrich is struggling but will be a free agent this offseason. Sure, they’re both in their thirties, but if the rule changes came tomorrow, these players become more valuable at minimal cost. Even if they do not fit into a rebuilders window to compete, they can instead become assets for a trade.

Will the catchers on your roster gain or lose value with robot umps? Are the pitchers on your current pitching staff going to be successful if they have to throw more strikes? Will their value drop if the shift goes away? If the mound gets moved back, will your current pitchers still be able to command the zone? Should catching instructors plan on teaching catchers to “stick” pitches rather than frame with a robot ump so that pitchers gain confidence by the loud pop of the mitt? These are all plausible questions, now is the time to be thinking ahead.

*One last reminder that this is based on 2019 season data.