Elite-level baseball is highly regulated and all equipment used on the field is subject to previous approval. With this in mind, it’s interesting to look at the equipment choices made on different levels, including college baseball and the MLB. Curiously enough, two different types of bats are used, prompting the question of whether wooden or aluminum bats are better.
Why does MLB use wooden bats?
To answer why MLB uses wooden bats and why college baseball uses metal bats, we need to take a closer look at the construction of each type of bat and the resulting properties it has on a baseball field. As it turns out, the difference mostly comes down to a single, hugely important factor – player safety.
What is the difference between wooden and metal bats?
Bats made of metal (typically aluminum) look similar to traditional wooden bats in terms of size and shape, but they don’t behave the same when used to hit a baseball. The type of material impacts how the ball bounces off the bat, which is a crucially important element of baseball that occurs many times in every game. Most importantly, the highly polished metal surface allows the ball to move at a greater exit speed, adding more punch to each hit and sending the ball further up the field. On the other hand, fast-moving balls can potentially endanger pitchers and other players on the field, particularly on a line drive that travels in a straight line approximately at head level.

Bat exit speed depends on two major factors – the power of the swing and the elastic properties of a bat. With aluminum bats, reasonably strong players can easily achieve speeds above 100 mph and potentially significantly more, a significant increase compared to wood. In particular, composite bats are known for being extremely elastic and facilitating high-speed action of the ball, as their design can specifically be tailored to this purpose. To compound the matter, metal bats tend to produce greater speeds as they are broken in and used for a while, which doesn’t happen with wooden equipment. That possibility opens the space for some players to intentionally wear out the bats and gain an edge.
Which type of bats is used for college baseball?
College baseball bats can be made from different materials, although they are required to conform to a general standard enforced by the NCAA. That means some metal bats are allowed at this level of competition, and a majority of players choose them over wooden bats due to the competitive advantage they create. NCAA decided to allow metal bats in 1975 and despite some criticism it continues to support their use, citing benefits to the game and excitement of the fans that come as a consequence of increased offense as the main reasons.
However, that doesn’t mean just any bat is permitted in college baseball. Composite bats have been banned since 2009, and a rigorous testing program was instituted in 2011 to control the properties of any bats proposed for on-field use. The testing includes an evaluation of the ball-bat coefficient of restitution, which is one of the most reliable indicators of the projected bat exit speed. The bounciest bats are eliminated from consideration, so the speeds are kept within a manageable range and the attempts to design bats specifically for maximum hitting power are somewhat restricted.
Why are aluminum bats illegal in MLB?

In contrast to college baseball, MLB does use wooden bats on an exclusive basis. Any aluminum or composite bats are strictly prohibited and may not be used in a game. While it may not be obvious why MLB uses wooden bats when aluminum ones are allowed in Little League and high school baseball, it’s necessary to consider how powerful most professional hitters are. Big league players can already hit the baseball very hard, and giving them extremely lively bats would tilt the game too much towards offense. Too high bat exit speeds would also present a safety problem with potentially fatal consequences.
The official MLB rules provide a very strict standard regarding which bats can be legally wielded by the players. This includes the dimensions, shape, and smoothness of the surface for any bat used for MLB play, in addition to the requirement that the bat must be made from a single piece of solid wood. Laminated or experimental bats have to be individually approved by the league in order to be considered legal, while any metal or composite bats are banned outright. While there is no official explanation why MLB doesn’t use metal bats, the standards are clearly set up to prevent any unfair practices.
Are aluminum bats really more dangerous than wooden bats?
Incidents involving a player being seriously injured or even killed by a batted ball are well-known, although admittedly rare occurrences in baseball. It’s beyond doubt that greater bat exit speeds increase the danger and shorten the reaction time, but the practical implications of using high-velocity bats on actual injuries are not entirely clear. This is why opinions are split regarding the use of metal bats for baseball, with one side supporting the absence of aluminum bats in MLB and asking for the ban to be expanded to all lower levels, and another group of experts citing a lack of hard evidence that metal bats truly cause more injuries as justification for their continued use.
Baseball will remain a dangerous sport up to an extent regardless of which safety measures are implemented, but the risks need to be managed smartly. Even a small increase of the bat exit speed can indeed add more risk, but more testing is required before a definitive answer can be found. Right now, only MLB does recognize the use of wooden bats as essential, although college baseball is taking some tentative steps in the same direction. At the very least, the most elastic bats should be kept out of the game, but where exactly to set the line remains a matter of debate.