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.