The following is from a Fan Graph Article. Its the author’s opinions on these 30 unwritten rules of baseball:

1. Never put the tying or go-ahead run on base.

This seems more like a “good idea” than a rule, as it’s not really something a pitcher can control. My guess is that if they had their druthers, they’d never put anyone on base.

2. Play for the tie at home, go for the victory on the road.

This one isn’t baseball specific, as you hear announcers talk about this rule in every sport. As I understand it, the idea behind this is that the home team is more likely to win in extra innings (or overtime in other sports), so extending the game is more likely to lead to a win at home. Given that we know that home field advantage is something like 54-46 in baseball, much smaller than in other sports, this is one that probably applies much more in football or basketball.

3. Don’t hit and run with an 0-2 count.

Actually, with two outs, that might be the best time to hit and run. A batter’s expected outcomes are awful in 0-2 counts (league average of .152/.160/.217 last year), so the harm caused by a caught stealing is significantly diminished. The idea is that you don’t want to force the batter to swing at a pitch out of the zone to protect the runner when he doesn’t have any strikes to give, but a modified hit-and-run where he only swung at strikes might be a really great strategy.

4. Don’t play the infield in early in the game.

In most circumstances, this one’s right on. Unless you’re facing Roy Halladay and think that one run might just be enough to win it, you’re better off conceding an early run in order to minimize the chances of more hits getting through and leading to a big rally.

5. Never make the first or third out at third.

Maybe a better way of putting this is “don’t take unnecessary risks on the basepaths” – any good baserunner is going to eventually make an out at third that breaks this rule, but the logic behind it is sound.

6. Never steal when you’re two or more runs down.

This seems too conservative for my tastes. In the ninth inning, sure, but if you’re down 4-2 in the seventh inning and you get a great base stealer on first base, having him take second can put you in a significantly better position to get that run in and make it a one run game. Maybe at four runs I’d agree that you’re better off not risking the out, but two runs is just too narrow a gap to completely shut down an effective running game.

7. Don’t steal when you’re well ahead.

This is more of a courtesy thing, and I guess it’s up to every manager to decide what is “well ahead”. What if you have a four run lead, a bad bullpen, and you’re facing the Tigers? Are you comfortable with that? If not, add on. I can get behind not stealing runs when your win expectancy is north of 97 or 98 percent, but I wouldn’t stop trying to score runs against a good offense just to satisfy this unwritten rule.

8. Don’t steal third with two outs.

This is just the “third out at third base” rule again. In general, it’s mostly right.

9. Don’t bunt for a hit when you need a sacrifice.

Totally disagree. There’s no reason to not try and get on base when you’re bunting, even when you’re sacrificing. Not making the out is far more valuable than making the out, so if you can get the runner over and get yourself to first base, by all means, do it.

10. Never throw behind the runner.

“Unless he’s retreating to a base after tagging up, or you have him in a rundown, or he’s strayed too far off the base and your catcher has a strong arm.” Too many exceptions for this to be a rule.

11. Left and right fielders concede everything to center fielder.

In general, this works out most of the time. Nothing wrong with this guideline.

12. Never give up a home run on an 0-2 count.

Same deal with rule #1 – if pitchers could not give up home runs, they wouldn’t, no matter what the count. The spirit behind this one is to not center up a pitch when you’re in an 0-2 count, which is good advice, but this could be stated a lot better.

13. Never let the score influence the way you manage.

As Matt Meyers pointed out, this one invalidates nearly all of the rules that came before it, which is fun. This one’s just totally wrong – the score should absolutely dictate how you manage.

14. Don’t go against the percentages.

This is great if the managers actually know what percentages matter. Feel free to go against “this batter is 1 for 7 lifetime against this pitcher” all you want.

15. Take a strike when your club is behind in a ballgame.

In other words, do whatever you need to do to get on base and start a rally. Of course, if you believe that taking strikes is more likely to lead to getting on base, then you should probably adopt this as a strategy all the time. Getting on base more often is never bad.

16. Leadoff hitter must be a base stealer. Designated hitter must be a power hitter.

Nope. Still widely believed, but just straight up wrong.

17. Never give an intentional walk if first base is occupied.

I’d probably add in an exception about 8/9 situations in the NL, especially if the run is critical and you don’t believe the opposing manager will hit for the pitcher, but this one’s mostly right.

18. With runners in scoring position and first base open, walk the number eight hitter to get to the pitcher.

Early in the game, yes. Late in the game, you have to evaluate the other team’s pinch-hitting options and whether you’ll have to make a pitching change in order to preserve the platoon advantage.

19. In rundown situations, always run the runner back toward the base from which he came.

This is a good way to teach the rundown to kids, but it’s not really practical as a rule. Once you throw the ball to the guy behind the runner in order to try and apply the tag, he’s going to run away from the base. You have to chase him to apply the tag. But this is nitpicking – the idea is good.

20. If you play for one run, that’s all you get.

Amen.

21. Don’t bunt with a power hitter up.

Amen squared. I’d probably expand to to good non-power hitters too, but many of them are fast and good at bunting, so no quibbles here.

22. Don’t take the bat out of your best hitter’s hands by sacrificing in front of him.

Amen to the third power. This anti-bunting section is awesome.

23. Only use your bullpen stopper in late-inning situations.

Meh – in the playoffs, I’d have no problem going to my best reliever early in order to keep the game close. In the regular season, I’m okay with this.

24. Don’t use your stopper in a tie game—only when you’re ahead.

No, no, a thousand times no. This one is just horribly wrong.

25. Hit behind the runner at first base.

Meh – I’d rather have my guys try to get on base themselves than focus on moving runners over. It’s an okay byproduct, but it shouldn’t be the goal. The goal should be to not make an out.

26. If one of your players gets knocked down by a pitch, retaliate.

Hopefully, this one will get phased out of baseball, but we talked about that the other day.

27. Hit the ball where it’s pitched.

“Unless you’re Jose Bautista, in which case, pull everything.” Again, decent advice to teach a youngster how to hit, but doesn’t really apply to most Major League players, who already have developed strengths and weaknesses at the plate. You don’t want your pull-power slugger just trying to loop every outside pitch the other way. If he can’t pull it, not swinging is probably a better option.

28. A manager should remain detached from his players.

I guess I don’t really have an opinion on this one. Maybe that’s better, maybe it’s not. I don’t know.

29. Never mention a no-hitter while it’s in progress.

For on field personnel, there’s nothing wrong with this one. It probably wouldn’t help anything to be actively discussing it in front of the pitcher, so an outright ban is fine. That some fans try to carry it over to announcers and those watching the game is silly.

30. With a right-hander on the mound, don’t walk a right-handed hitter to pitch to a left-handed hitter.

But apparently, it’s totally okay for an LHP to walk an LHB to get to an RHB? This is basically just “don’t give up the platoon split”, but there are way too many exceptions to make this a rule. If your RHP wants to walk Dustin Pedroia to get to Nick Punto, that’s fine with me.