MLB required players to use smaller bats in 2010. Royals Authority talked to an expert:
“It should not make any difference to home runs or any other batted balls if the bat strikes the ball near the middle of the bat. The only difference would be in those cases where only the edge of the bat strikes the ball. So, there would be an increase in the number of complete misses or strikes, possibly by the same fraction as the change in bat diameter.”
That makes sense. Mark McGwire used to say you could hit a home run with a pool cue if you centered the ball. According to Baseball Reference, 20.8% of swings missed in 2010. In 2009, it was the same, given the number decimal points BR publishes. It seems to me the biggest difference would be balls that were either foul pops or beat straight down would be swing and misses.
Hat tip, Halos Heaven.
Absolutely unbelievable that none of the mainstraem reporters (and I use the word loosely) at MLB, ESPN, local newspapers, etc were able to pick this up. I mean, I would think players and coaches would know about it and comment on it to reportters asking about it. Maybe the MLB powers that be discourage discussion on this matter, but that would be a conspiracy theory. LOL
Also, the article mentions that HR rates were unchanged, but if you look at the leagues separately, you will see the AL had a SIGNIFICANT drop (16%), after the previous years 13% increase.
A smaller diameter with the same length reduces the bats weight. Perhaps as much as 11% if the proportions are maintained from the bat head to handle. That would reduce the energy transmitted from the bat to the ball by as much as 11%.
Half of hitting is mental, so say some, and having a smaller bat may affect hitters confidence.
I remember 20 or so (give or take 5 years) there was an article in a science magazine (maybe Nature?) that said that lighter bats hit the ball further. I’m not sure about the details of the physics, but I think that since the batter can swing it faster, it knocks the ball further. (This is the reason for corking the bat, I believe. It makes the bat lighter. I guess it’s illegal because it’s lighter but has the same surface area.)