How Will The 2023 MLB Rule Changes Impact The Seattle Mariners?

There are a few significant rule changes on the way for 2023; some of them may mightily impact teams across the league. Teams won’t be able to shift their infielders like we are used to seeing now, bases will become bigger, and pitchers are limited in their ability to keep runners on base in check. But, the big question is how do these rules changes impact the 2023 Seattle Mariners?

Stealing bases will become easier, which means catchers have to work harder than ever

All bases are now going to be 18 inches square instead of 15 inches square which will make it easier for runners to steal a base. Although it seems like a minor change, baseball is a game of inches and the minor leagues prove it.

Stolen base attempts in the minor leagues increased from 2.23 times per game to 2.83 times per game. The success rate jolted up from 68% success rate to 77% success rate via USA Today. So with that being said, catchers will be relied upon more often than we’ve been used to.

At a glance, I think most Seattle Mariners fans would agree that Cal Raleigh is a good catcher. He threw out the second-most runners in the MLB behind J.T. Realmuto and ranked 4th in Catcher Framing Runs according to Baseball Savant.

Awesome right? Yes, Cal Raleigh threw out a lot of runners but that is also because many people attempted to steal with him behind the plate.

Among catchers who caught at least 500 innings in 2022, Cal ranked 9th in runners caught stealing percentage. As expected, Realmuto led the league with a 44.12% caught-stealing percentage.

Kyle Higashioka followed with 40.63%. Yadier Molina with 39.39%, and Salvador Perez at 34.48%. Raleigh threw out 32.05% of runners. And when you look at stolen bases allowed, Raleigh allowed the fourth most during the regular season.

Furthermore, Cal Raleigh ranked 9th among all catchers in rSB, which is DRS-stolen base runs above average. According to FanGraphs, this measures how a catcher compares to the average catcher in terms of preventing stolen bases. 9th in the MLB isn’t bad at all, but there is a stark difference between Raleigh and the elite catcher, Realmuto. The Phillies catcher led the league with 9 defensive runs saved while Cal had 2.

Another important metric to look at for catchers in this situation is pop time and arm strength. Among all catchers, Raleigh ranked 19th in average arm velocity according to Baseball Savant. Christian Bethancourt led with 88.3 mph compared to Cal Raleigh’s 83.8 mph.

What is worrisome for me is his exchange time. The soon to be 26 year old’s average exchange time was 0.79 seconds which ranked 76th in the league. With those two metrics in mind, Cal’s average pop time to second base was 1.99 seconds which ranked 44th in the league.

For comparison, Curt Casali had a 0.73 second exchange time and 2.01 second average pop time. Luis Torrens had a 0.75 second exchange time and a 1.99 second average pop time.

With all this being said, I am not calling out Cal Raleigh’s defense at all. He made huge strides in the minor leagues after being viewed as an offensive-first type of catcher as a prospect. But, I do think we need to keep in mind that the former third-round pick isn’t an elite catcher right now and the opposition might try to take advantage in 2023.

The good thing for us Mariners fans is that Raleigh did throw out a bunch of runners and showcased his potential. I wouldn’t be surprised if the coaching staff works on speeding up his exchange time because I really do think teams will try to take advantage of the larger bases and the limits to pitchers holding runners.

Now, catchers aren’t the only ones that are responsible for stolen bases. Let’s take a look at a few numbers on our pitchers and team stats.

Pitchers will have a tougher time controlling the run game, what about the Mariners arms?

Pitchers also play a big part in controlling the run game but things get a little tougher next season. The MLB has decided to enforce new rules to continue the effort to create a quicker-paced game.

Between pitches, there will be a 15-second timer when the bases are empty. With runners on base, pitchers have 20 seconds. Pitchers who violate the timer are charged with an automatic ball.

Of course, batters won’t be just allowed to stall to take advantage of this rule. Batters must be in the box and alert the pitcher by the 8-second mark or they will be charged with an automatic strike.

In addition to a strict timer, pitchers can only disengage from the rubber twice per plate appearance. The limit does reset if a runner advances during the plate appearance but this is another complexity that gives an advantage to base runners.

So, if Robbie Ray made one pickoff attempt and stepped off to wipe his sweat in the same plate appearance, the runner at first would have a major advantage; Ray has no option but to throw the pitch or give the runner a free advancement if he does disengage.

I, unfortunately, couldn’t find very good data on stolen bases allowed by pitchers. I did come across a site called Razzball which had data from 2019 to June 6, 2022, but it doesn’t seem to be an exhaustive list of MLB pitchers.

What I was able to find on the data source was information on Robbie Ray, Marco Gonzalez, Justus Sheffield, Luis Castillo, Logan Gilbert, Chris Flexen, and Matthew Boyd. Guess who allowed the most stolen bases per inning?

Justus Sheffield and Robbie Ray nearly allowed 0.1 stolen bases per inning. Robbie also allowed the second most steals in the Razzball timeframe. Noah Syndergaard allowed 56 stolen bases which was the most and were roughly equal to 0.2 steals per inning.

Out of the Seattle Mariners pitchers that were listed on the data source, Matthew Boyd, Chris Flexen, Luis Castillo and Marco Gonzales had the lowest stolen bases per inning ratio. To be honest, this doesn’t come as much of a surprise to me. I would consider these pitchers as the more athletic of the group and a little more conscious of their surroundings.

Logan Gilbert also had high stolen bases per inning ratio of 0.08. Another metric to note, Chris Flexen, Logan Gilbert, and Robbie Ray had the highest stolen base success rate in this bunch.

Obviously, these numbers are a very small group of Mariners pitchers which doesn’t provide a whole lot of context. But, looking at total stolen bases allowed on a team basis might help.

The Seattle Mariners ranked 19th in stolen bases allowed per game during 2022. The Mariners gave up 0.56 bases per game, while the Cardinals and Yankees tied for the least amount of stolen bases per game at 0.30. This shouldn’t come as much of a surprise since they have Yadier Molina, Jose Trevino, and Kyle Higashioka behind the plate for most of their games.

From the eyeball test, you feel like the Seattle Mariners were decent at holding the run game but the numbers say otherwise. I am sure every MLB team will be having conversations with their pitchers and catchers on figuring out how to counter the advantage given to runners in 2023. The Mariners will certainly need to make a group effort to adapt and control the run game.

Now, let’s move on to defensive shifts cause that is an interesting one for me.

Seattle won’t be the only team benefiting from a ban on shifts, but these Mariners players will

The MLB will be taking a big step backward in defensive shifts and essentially bans what we now know as a shift. Four infielders must be within the outer boundary of the infield, infielders can’t switch sides, and there must be two infielders on each side of second base.

So, how does this impact the Mariners offensively? On Baseball Savant, they do a really good job of tracking players who hit with a shift on or not and a player’s wOBA based on it.

Among Seattle Mariners, teams moved their infielders 96.2% of the time when Cal Raleigh hit left-handed. That was the 4th most frequent among MLB players. Even with the shift on, he hit for a .330 wOBA which is good. For context, Aaron Judge had a .458 wOBA in 2022, Shohei Ohtani had a .370 wOBA, and Julio Rodriguez had a .366 wOBA.

What is even greater is that without a shift in place, Cal posted a .419 wOBA. So, will we see even better numbers from the catcher in 2023? I mean infield shifts don’t play a role in home runs or balls in the alley, but it does make a difference in those hard groundballs into right field.

Jarred Kelenic should also greatly benefit from this new rule. With a shift, which was set 86.7% of the time for him, he posted a .226 wOBA. But without a shift, Kelenic posted a .316 wOBA.

Another player that should improve is Mitch Haniger (another reason why we should re-sign him). Mitch had to hit against the shift 71.1% of the time last season and posted a .260 wOBA. Without the shift, he posted a .465 wOBA which is quite a stark difference.

There are also two other players who had differences between a shift and no-shift set against them. Abraham Toro posted a .214 wOBA while having a shift against him 77.4% of the time. Without a shift, he had a .369 wOBA.

Sam Haggerty, as a left-handed hitter, had the shift on 42.1% of the time, and his wOBA was .137. Without one, he posted a .303 wOBA.

It’s also interesting to see how some players found more success when the shift was against them. Jesse Winker for example posted a .327 wOBA when the shift was against him 76.1% of the time. When hitting without a shift, he posted a .270 wOBA. J.P. Crawford also benefited when the shift was implemented. Crawford had a defensive shift against him 16.1% of the time and posted a .340 wOBA.

And of course, I am sure you’re asking about our star player Julio Rodriguez. But, Julio only had the shift against him 8.3% of the time and in those situations, he posted a .263 wOBA. Without one, which is basically most of his at-bats, his wOBA was .374.

The same goes for Dylan Moore and Ty France. They were largely unaffected by a defensive shift and most teams rarely shifted probably for this reason. Dylan hit against the shift 2.8% of the time while Ty France hit against the shift 2.1% of the time. Now, let’s stay on a similar topic and cover the defensive implications of the ban on shifts.

Will larger bases lead to more stolen bases from the Seattle Mariners?

Two big rules will impact the running game in 2023. First, the distance between first to second, and second to third will decrease by 4.5 inches. Second, pitchers have time restrictions and a limit on disengagements.

These new rules were tested in the minor leagues and boosted stolen base attempts and success rates. Stolen base attempts jumped to 2.83 attempts per game, compared to a previous 2.23 stolen base attempts per game. The success rate of stolen bases also went up by 9%, going from 68% to 77% success rate.

I am sure this trend will be seen in the big leagues as well but will the Mariners be able to take advantage?

Last season, the Mariners stole 83 bases as a team which is in the middle of the pack. The stolen bases from the Mariners came from just 9 players with Julio Rodriguez and Dylan Moore leading the group.

The Texas Rangers led with 128 stolen bases and had 20 players contribute to that total. The Rangers are in a bit of a different situation because of the constant rotation of players in that lineup but the diversification of stolen bases is something we might expect from the Seattle side next year.

When looking at stolen bases under Scott Servais, 2016-2022, the Seattle Mariners are actually 12th among MLB teams with 536 steals. So, being aggressive on the basepaths isn’t something that is necessarily out of the ordinary for the Mariners.

Obviously, it is not all on Scott Servais and the coaching staff on how many steals the team can get but it is in his history. In fact, the Mariners finished 5th in stolen bases in 2019 with 115. And then in 2020, the M’s were 3rd in stolen bases with 50, just 5 behind the Padres who led the league.

Now, let’s get into sprint speeds from last season courtesy of Baseball Savant. The Seattle native Corbin Carroll led all players with an average 30.7 ft/sec sprint speed. Julio Rodriguez however isn’t too far behind at 29.8ft/sec. Julio finished with 25 stolen bases in the regular season and that number might exceed 30 next season.

Sam Haggerty had an average sprint speed of 28.9 ft/sec and is another speedster that could greatly benefit from the rule changes. He stole 13 bases last season which means he stole a base every 6.5 games. If he gets more time, he could be a significant impact on the run game. I wonder if Servais will get him more time because of the advantage given to runners on base.

I also expect Dylan Moore and Jarred Kelenic to cause chaos and get into the scoring position. Moore is undoubtedly one of the better base stealers on the team and Kelenic could make large strides next season as he gains another year of experience under his belt.

There might also be a few stolen bases from people we didn’t see a whole lot from last year. J.P. Crawford only logged 3 bases but I expect double digits from him in 2023. Taylor Trammell is another candidate for 10+ steals if he gets time on the field.

Let’s also not leave out Cal Raleigh who did log one steal in 2022. His average sprint speed was 26.8 ft/sec which is the same average as J.P. Crawford in 2022, surprisingly. Maybe we get 5 bases from Cal?

I could go on and on about who could contribute to the stolen base totals for the M’s. Overall, this will be something that will be seen across the entire league I’d imagine, much like the other things I have addressed in this article.

It will be interesting to see how the Mariners take advantage of these rules and how some of these rules will negatively impact the team. There is a great opportunity for the Mariners to win the offensive and defensive impacts of the ban on shifts. They also have a great opportunity to improve their run game with the speed that they already have.

I am however slightly worried about how teams will test Cal Raleigh and the pitching staff with runners on base. There will need to be a lot of work done by the coaches to work with pitchers on controlling the run game in a much different situation than in the past.