Here's How Triple-A Will Test New Bases In 2021
The switch to a new base for Triple-A leagues will be a little more involved than what was first reported.
To be able to measure any differences in how the game is played and if the new bases can reduce the risk of injury, Major League Baseball will have Triple-A East and Triple-A West split time between using a 15 x 15 inch base and an 18 x 18 inch base.
In the first half of the 2021 season, Triple-A East will use an 18-inch bag manufactured by Schutt. That is the same base that was used in the Atlantic League in 2019. For the second half of the season, the league will shift back to a standard 15-inch bag.
While the East will be switching back to a traditional 15-inch bag halfway through the season, Triple-A West will be switching to an 18-inch bag. But the bigger bag in the West will be a new design built by Boombang.
That bag is designed to have a reduced height (it’s only 2.5 inches tall at the center of the bag compared to the current 3 inches), a more gradual/less squared profile on the sides and different textures and grooves.
By having both leagues operate half the season with one base and half with the other, it will provide a control group to demonstrate any differences. A similar approach was used in the Atlantic League in 2019 with multiple rules. By adopting a new pickoff rule at midseason, MLB was able to see that the changes to the rule led to a significant increase in stolen base attempts.