Mizuno Corp. President Akito Mizuno apologized on Tuesday following revelations that baseballs his company had supplied to Nippon Professional Baseball this season were livelier than the permissible limit.

"Due to our own clumsiness, we have caused a lot of trouble for everyone. I want to apologize from the bottom of my heart," Mizuno said at a news conference held in Tokyo.

NPB's tests on balls after the start of the season found the coefficient of restitution, which compares a ball's speed after and before impact, to be higher than the allowable limit. According to Mizuno, the rise in the COR levels was likely caused by the dryness of the woolen yarn wrapped around the core of the balls.

He suggested that about 2,300 dozen ball packs ready for delivery will be screened, and balls meeting NPB's specifications will be delivered starting by April 22, at the earliest.

Mizuno also said production will begin on balls that comply with NPB regulations, and that a steady supply of those balls could be possible by early May.