Adhering to a Little League International decision to ban composite baseball bats to all of its divisions, Wellesley Little League will not allow such bats in any of its leagues this season.

Composite bats have a metal sheath on the outside and a woven graphite wall inside. Little League says some of the bats can meet safety standards when new, but can fall below standards once broken in. Research from UMass-Lowell’s Baseball Lab showed the potential danger to pitchers and fielders from such bats.

Approved aluminum bats, which were re-introduced last season after years of not being allowed due to injury concerns, can still be used.