I’m sitting here, reading complaints on Twitter. Not long ago, a starting lineup was revealed for a Tuesday baseball game, and almost immediately some people took issue. They don’t like that a certain bench player is getting a start, and they don’t like that a certain regular starter is sitting out. Why, they wonder, would you ever make your lineup worse, especially when you’re playing against a team in the same division?

To be perfectly honest, yeah, this is inspired by the Seattle Mariners. But this isn’t just a post about the Mariners, because this can apply to every team and to every team’s fan base. There’s not a single fan base immune to lineup complaints, and as much as more people are beginning to understand that lineup order doesn’t make much of a difference, a bench player filling in for a starter always generates a negative response. After all, the bench player, presumably, is worse than the starter, which is why the starter is the starter. So what does it mean to take out a starter?

I’m talking about sitting a guy on a single-game basis. The negative commentary I’ve read today is about Willie Bloomquist slotting in for Dustin Ackley. Bloomquist’s worse than Ackley, most likely. But every manager starts a bench player sometimes. Let’s play around with the significance, and offer examples in the form of win expectancy. What I mean will become clearer in a minute.

The best player in baseball is Mike Trout. I don’t think anyone doubts that. Even the people who voted for Miguel Cabrera for MVP acknowledge that Trout is the best player overall. Two years ago, Trout was worth 10 WAR. One year ago, Trout was worth more than 10 WAR. This year, Trout is on pace to be worth more than 12 WAR. Combined, ZiPS and Steamer project Trout as a 10-win player over a full season. So the worst thing a manager could do would be to sit Mike Trout and start some replacement-level substitute. If that were to be done, then the Angels’ odds of winning the baseball game would drop by about 6.1 percentage points.

What’s the equivalent of 6.1 percentage points, in win expectancy? Let’s say you’re the road team. Let’s say your chances start about 50/50. To have your win expectancy drop about 6.1 percentage points, you’d need to have a scoreless top of the first, and you’d need to start the first batter of the bottom of the first with a ball. That’s what substituting Trout would be worth — three automatic initial outs, plus a ball.

And that’s Mike Trout. Let’s try some different players. Instead of Trout, let’s say you start a bench guy for Miguel Cabrera. The Tigers’ odds of winning would drop by about 4.0 percentage points. The equivalent of that in win expectancy? You’re the road team, and the top of the first begins with two outs. You don’t concede the whole half-inning, like you do in the Trout example, but you get most of the way there.

Bryce Harper? Starting a bench guy for Bryce Harper? The Nationals’ odds of winning would drop by about 3.1 percentage points. That’s like conceding the first out, and then having the second guy start out 0-and-1.

Starting a bench guy for David Ortiz? The Red Sox’s odds of winning would drop by about 2.4 percentage points. That’s like conceding the first out.

Starting a bench guy for Carlos Beltran? The Yankees’ odds of winning would drop by about 1.8 percentage points. That’s like conceding the first two strikes of the game’s first plate appearance.

Every single substitution — they all matter. A team is weakened by a bad player playing in place of a better player. If you sit Mike Trout for a game, it’s like giving away the first half-inning of offense. But, a few things. (1) No other player is Mike Trout. (2) Leverage is low in the top of the first. (3) Boy are there ever other considerations.

Figure that a bench player doesn’t start for a starter for no reason. There’s always some reason, as managers don’t fill out lineup cards randomly. And because there’s a reason, you have to figure the gap between the bench player and the starter might be smaller. Or, if the gap isn’t smaller on that particular day, the manager might have an eye toward future benefits. Maybe he needs to keep the bench player content. Maybe he needs to keep the bench player fresh. Maybe he needs to give the starter a rest, because if he played every day, the starter could wear down.

Maybe the starter’s sick, or in some discomfort. Maybe there’s something about the particular pitching matchup. There’s a lot that can go into a lineup decision, and while it’s an essential pastime of the pastime to criticize team managers, managers need to be given some benefit of the doubt. They are particularly informed, and while that doesn’t prevent them from making bad decisions, it does mean that perceived bad decisions could have very reasonable explanations. You might not like when a starter sits for a bench player, but it could have a long-term benefit. In the moment, unless the player is really, really, outstandingly good, the impact of the substitution is pretty small. It might be like one out. It might be like one strike. It might be like one gust of wind blowing one speck of dust into one hitter’s eye before the first pitch of the game. This doesn’t even say anything about the possibility of the sitting starter pinch-hitting later on.

There’s just precious little point in complaining about single-game lineups. Even perceived suboptimal decisions make little practical difference, and we’re not always privy to reasons for the decisions that might reduce the impact. Which isn’t to say you can never justifiably complain. A pattern of weird substitutions would be worse. Consistently sitting a decent player would be worse. Consistently running out a lousy lineup arrangement would be a problem. Starting the wrong guys in the playoffs would be terrible, when the stakes are their highest and there’s an abundance of off-days. But as I write this, it’s April 15, and a bunch of teams are preparing for a regular-season baseball game. Some of those teams are going to have bench players starting in place of superior regulars. Some of the fans of those teams are going to really not like it. And it’s probably going to really not matter. Complaining’s a good tool. You don’t want to wear out your good tools.