How Meaningful are Opening Day Starts, Really?

Baseball, perhaps more than all other American sports, values tradition. That emphasis on existing conventions is part of what makes baseball special. However, a predisposition to doing things “how they’ve always been done” makes for sometimes complicated dynamics. New ideas that challenge tradition are oftentimes met with skepticism, or worse. One need not look beyond the polarizing presence of sabermetrics in baseball circles to epitomize this struggle between longstanding traditions and emerging trends.

One area of baseball tradition that has been of interest to me is Opening Day. More specifically, who gets the ball.

Of course, there is a certain amount of esteem associated with starting on Opening Day. Every spring, there is no shortage of articles discussing the health of a projected Opening Day starter, a competition between two players competing for the honor, or how many years a pitcher has made an Opening Day start in a row for his team.

What is interesting though is that Opening Day decisions are sometimes based on tradition as much as skill. While all teams have a vested interest in starting their seasons with their best pitcher on the mound in order to line up against their opponents best as well as to maybe squeeze in an extra start for that individual over the course of the season, tradition also often comes into play.

Put simply, the Opening Day starter calculus is fuzzy. Should a team bring in a new pitcher who sits atop the rotation depth chart but have another veteran who has been part of the team for a solid stretch and is also quite good, sometimes a team might defer to that fan favorite. In some cases, though, the newcomer is so much better than the alternatives that they are automatically installed as Opening Day starters (see Jacob deGrom, 2023 Texas Rangers). A pitcher who is recovering from a minor spring training injury might either rush or pace himself for Opening Day, depending on if he has had the chance to start on Opening Day before. Sometimes there is a “changing of the guard” – like Walker Buehler starting Opening Day in 2022, interrupting Clayton Kershaw‘s streak.

All this is to say, pitching on Opening Day is something of a big deal. However, how big a deal likely depends on who you ask. That said, I figured it would be an interesting exercise to try and quantify (or at least contextualize) getting the ball to start your team’s first game of the season.

The best comparison criteria that I could think of were All-Star appearances, so that is what I used. Generally the question then being: is it rarer to be an Opening Day starter or an MLB All Star (as a pitcher)? It should be noted that this comp is far from perfect and this exercise is far from rigorous, but it makes for good context at a glance.

Data comes from two sources. For All Star appearances, Sean Lahman’s database provides all that one might need and more. For Opening Day starts, Baseball Reference provides pages for all franchises and rosters.

First, the Opening Day data.

From 2000-2021 (excluding 2020 in order to match ASG selections) there have been 630 Opening Day starts, i.e. 30 starts/starters per season for 21 seasons. However, that number does not account for the number of repeat Opening Day starters. When looking at distinct Opening Day starters over that same time period the total falls drastically to 271.

Below is a list of those individuals that started on Opening Day the most within the timeframe defined.

There is three-way tie at the top between some familiar names: Félix Hernández, C.C. Sabathia, and Justin Verlander. This top-15 list doesn’t suggest a stark dropoff though after those three names; quite a few other pitchers made a half dozen-plus Opening Day starts themselves.

Still, a broader view of the distribution of Opening Day starts underscores how much more often pitchers got the ball to start a season just once or twice. Overall, just over half (50.6% – 137 of 271) of Opening Day starters over this timeframe had the honor just one time. The histogram below illustrates that breakdown.

How do these numbers compare to All Star selections, though?

When it comes to total selections, the number of All Star pitcher choices is not set from year to year, as is the case with Opening Day start(er)s, which is bounded to 30 annually. Accordingly, from 2000 to 2021 (and excluding the pandemic-shortened 2020 season) there have been 596 All Star pitcher roster spots, or ~28 per year. Annually, the total of selected All Star pitchers seems to be on the rise, likely due to pitcher injuries and the resulting alternate selections.

That 596 number does include relief pitchers, so those who really care will note that this isn’t a strict apples-to-apples comparison.

So, All Star selections for pitchers are slightly less numerous than Opening Day nods, but they are absolutely in the same ballpark. What about when looking into distinct pitchers, though? Can more pitchers say they made an All Star team than can counter that they got the ball to start their team’s season? In a word, no. Of those 596 ASG selections, 314 were handed to individuals.

Thus, Opening Day starters are a bit rarer than All Star Pitchers, when considering unique individuals. While there were 34 more Opening Day starts than ASG selections from 2000-2021 (again, excluding 2020), there were 43 more individual All Stars.

The leaderboard below highlights those with the most ASG selections.

Two things jump out: first, a handful of relievers, led by Mariano Rivera, were mainstays in All Star Games over the last couple decades. Second, the dropoff in appearances in this leaderboard appears a bit more pronounced than in the case of the Opening Day starts leaderboard.

A histogram of ASG selections seems to verify that observation.

Overall, 52.7% of All Star Game selections received the honor just once, a greater percentage than the one-time Opening Day starters (50.5%), which contributes some to an even more concentrated distribution in the case of ASG selections.

None of this is to say one honor is more important or meaningful than the other. Still, MLB All Stars can carry that distinction for the rest of their lives, so to realize that there are in fact fewer Opening Day starters is an interesting point given the relative lack of fanfare (outside of spring training articles) around that particular honor, at least. And for that reason, I would assign, purely as a fan of baseball, a fair amount of meaning to starting on Opening Day.