By Chris Cwik

Baseball is a game full of cardinal rules. They've been a part of the game's culture longer than anyone can remember, are never questioned and are ingrained into a player's head during their first year in little league. Hitters learn at a young age to never swing at a pitch in a 3-0 count. This bit of game theory is accepted even at the highest levels of the game. But that's being tested this season. Hitters are swinging away more often in 3-0 counts, and it might not be such a bad thing.

Swing rates in 3-0 counts have risen to 9.3 percent in 2013. While that might not seem like much, that number has been trending up since 2010, when it was just 6.7 percent. Considering the sample is roughly 8,000 chances per year, that's a significant increase.

The Nationals have been one of the teams to embrace the trend. "I love to hit 3-0," Nationals manager Davey Johnson told The Washington Post in August. "You just look for a ball the size of a basketball, in the part of the plate you want it." Johnson's rationale highlights the thinking behind swinging in that situation. If a hitter knows they are going to get a good pitch, why not take the chance?

On the surface, there's some evidence that supports Johnson's claim. This season, batters are hitting .361/.949/.739 in 249 at-bats in 3-0 counts. Looking back at the past couple seasons, the numbers are just as strong. 

The chart below shows all plate appearances that ended on the 3-0 pitch. It also includes intentional walks, which skews the on-base percentage. Even when those are stripped out, it doesn't make a huge difference. If you stripped out the 857 intentional walks from this season, on-base percentage would drop to .930.

3_0counts_chart1

The reason for the high batting average and slugging percentage in these counts is that hitters know exactly what's coming. Pitchers have thrown fastballs, or variations of fastballs -- cutter, sinker -- over 90 percent of the time since 2007. Fastball usage in these situations is rising, too. It's gone from 90.7 percent in 2007 and has settled in a little above 94 percent since 2010. It's the ideal situation for a good fastball hitter to strike. On top of that, there's a good chance the pitch will either be a strike, or close enough to induce a swing. Over that same period 58 percent of 3-0 pitches have been thrown for called strikes. When you add in plays where batters swung, that number jumps between eight to 10 percent depending on the season. The eight to 10 percent includes swinging strikes, foul balls and all hit balls. Hitters are working with a scenario where the ball is in the zone roughly 65 percent of the time. That's higher than the average first pitch strike rate, which is 60.3 percent this season.

3_0counts_chart2

The downside of swinging is that a hitter is highly likely to reach base if they keep the bat on their shoulder. Pitchers throw a ball about 35 percent of the time during 3-0 counts, though that number has dropped to 33 percent the past two years. On top of that, taking a pitch still puts a hitter in a desirable situation, and gives the pitcher at least two more opportunities to give up a walk. While a hitter's slash line drops in a 3-1 count, it's still strong. For example, batters are hitting .346/.681/.639 in 3356 at-bats in 3-1 counts. The argument for not swinging during a 3-0 count is that you are still in a pretty great situation if the count falls to 3-1.

At the same time, there are certain situations where a hit is more valuable than a walk. Late in a tie game with a runner in scoring position, teams are far more likely to risk making an out to move a runner over. Getting that runner across the plate is more important than the batter taking a walk. Opposing managers aren't dumb, though. If Miguel Cabrera happened to work himself into a 3-0 count in that situation, the opposing team would likely elect to throw an intentional ball and put him on base. It's also riskier for the hitter to swing with a runner on first, as the threat of a double-play would ruin a potential scoring opportunity.

While it's risky to pass up a high on-base scenario, there is some evidence that hitters should swing more often during 3-0 counts. It's one of the few times a hitter knows exactly what pitch is coming, and can guess with some confidence that it will be in the strike zone. Given that hitters have performed well in the past in a 3-0 count, it's worth a shot to go for the big play occasionally. It is even more acceptable in late, close games, when a team is playing for one run. Baseball's cardinal laws may disagree, but some situations call for the rules to be broken. 

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Chris Cwik writes for various baseball sites on the internet, CBSSports.com and FanGraphs.com. He has also contributed to ESPN and the Hardball Times Baseball Annual. Follow him on Twitter at @Chris_Cwik.