By the numbers: Opening Day impact of all those MLB rule changes

Some of the rule changes implemented this season by MLB were clear Opening Day hits. At least one major one, however, was a more qualified success.

Over the winter, MLB implemented the broadest array of rule changes in decades, changing the way the game is played in several ways. Those rule changes got their first official workout Thursday when all 30 teams were in action under them for the first time.

Those rule changes included:

• Banning extreme shifts by requiring infielders to have two feet on the dirt, and permitting only two on either side of second base.
• Creating a time clock stipulating that a pitch must be thrown within 20 seconds with runners on base, within 15 seconds with none on.
• Enlarging the bases and restricting the number of times a pitcher could throw to an occupied base, both in the hope of re-engaging the long-dormant running game.

The data from Thursday’s 15 openers was clear and decisive on one of those goals. Games were significantly quicker.

The average MLB opener Thursday required 165.07 minutes — about two hours and 45 minutes — to complete. That was nearly 30 minutes shaved off the average three hours and 16 minutes required to play each team’s opener in 2022, and 18 minutes less than the length of the average MLB game last season.

In percentage terms, that’s a speedup of 16 percent over last season’s Opening Day and 10 percent over the 2022 season-long average.

Of the 15 season-openers in 2022, only two were played in under three hours. On Thursday, 10 of the 15 were completed before the three-hour point.

The data on increased stolen base attempts was equally positive. Perhaps due to the larger bases, perhaps due to the limitations on throw-overs or perhaps by coincidence, MLB teams attempted an average of eight-tenths of a steal during their Thursday openers.

That may not sound like much, but it more than doubled the less than four-tenths of a steal attempt per team on last year’s Opening Day games. It also represented an 18 percent increase in steal attempts over the 2022 season-long average of 0.67 per team game.

The enthusiasts in this category were the Baltimore Orioles, who sprung five steal attempts on the Boston Red Sox Thursday at Fenway Park. No other team tried more than two; 14 teams did not attempt a steal Thursday.

Still, that was a measurable upgrade from 2022, when only 11 teams even attempted a steal. The Giants were alone among those 11 last season in attempting two.

Less decisive, but still positive, was the impact of the shift rule on improving offense. Scoring was up Thursday, averaging 4.37 runs per game compared with 4.13 for Opening Day 2022 and 4.28 for the entire season.

Base hits also increased, from 7.2 and 8.16 for 2022 Opening Day and season to 8.27 Thursday. That was a modest but still measurable 1.3 percent gain against the full 2022 season. Against Opening Day 2022 alone, the percentage increase was a more noteworthy 15 percent.

The most significant sub-number in this respect is the percentage of balls actually put in play Thursday. After all, if a ball isn’t hit the positioning of fielders is irrelevant.

During Thursday’s openers, 76.1 percent of plate appearances ended in a ball being put in play. For this instance, “in play” refers to a plate appearances that does not end in either a walk, strikeout, hit batter or home run.

That percentage was up, although only barely, from the 75.93 percent of balls in play last Opening Day, and from the 75.49 percent of balls put in play for the 2022 season as a whole.

The percentage increases were 0.2 percent across Opening Days and 0.8 percent compared with the entire season.

Home runs were off Thursday compared with 2022, both on Opening Day and for the entire season. Teams averaged 0.87 bombs Thursday as against 1.07 for both 2022 categories.

Teams were issued 3.57 bases on balls Thursday, fewer than the 3.87 they got during 2022’s opening day but more than the 3.06 season-long average.

The noticeable difference was in strikeouts. Thursday’s average was a healthy 9.63, thanks in large part to the 15 or more run up by the Rockies, Yankees, Giants and Reds. Last season’s Opening Day average was just 8.63, with only one team — the Yankees — striking out 15 times. The 2022 season-long average was 8.40.