Baseball manufacturer Mizuno may have been juicing this year's balls beyond the allowed limit without the knowledge of Nippon Professional Baseball.
NPB on Thursday said random tests have shown that balls from six stadiums used on March 29 were livelier than they should have been. NPB plans to re-test the balls, but has ordered Mizuno to explain why the balls tested above the limit.
"We apologize for not being able to identify the reasons for this," NPB executive secretary Atsushi Ihara said. "But we hope to find out why with swiftness and adjust it to the standards we've all agreed on."
In October, Ryozo Kato resigned as NPB commissioner to take the fall after the ball used last season had been secretly altered without his knowing.