The beanball is one of the scariest plays in sports, a baseball hurtling at the head of a batter who cannot get out of the way. Over the years, they have led to concussions, skull fractures and, in a handful of cases, deaths.

Helmets introduced starting in the 1950s have eliminated the most tragic risks. But mindful of the growing focus on safety in sports, manufacturers have tried to design helmets that offer batters a better chance of preventing head trauma.

For Rawlings, the official provider of helmets to Major League Baseball, the S100 Pro Comp is the latest and best attempt at protecting players. Introduced last year, it is fractions of an inch larger and an ounce or so heavier than a traditional helmet. But its carbon fiber shell is also 300 percent stiffer and 130 times stronger than the helmets made with plastic shells that have been the standard for the past several years.

About 200 players, including stars like Carlos Beltran, Matt Kemp and Buster Posey, wore the S100 Pro Comp at some point last season. But starting this spring training, all major league players must wear the helmet, a decision included in the collective bargaining agreement signed in 2011. The only exceptions are for the handful of players who wear helmets with earflaps on both sides.