Nippon Professional Baseball commissioner Ryozo Kato said Wednesday he had not been informed of changes made to this year’s ball to make it more lively.

Kato said the decision was made last year by NPB secretary general Kunio Shimoda, and that Shimoda had done nothing wrong in either ordering changes to the ball or not informing him of the decision.

“What he did was to make sure the ball met agreed-on specifications,” Kato told a press conference at NPB’s headquarters in Tokyo. “It did not go beyond the parameters set by the Baseball Charter (NPB’s governing document). Therefore, there was no need for me to be informed. I want to strengthen communication and management practices within the organization.”

“When I said (in April) that no changes had been made to the ball, I sincerely meant it. I was not concealing anything. I was telling the truth as I knew it.”

According to Shimoda’s lieutenant, Atsushi Ihara, only he, Shimoda and two officials of the ball’s manufacturer, Mizuno Corp., knew of the changes that were ordered last year.

Following routine tests of balls used by NPB’s 12 teams last year, too many balls tested were not lively enough to meet the standards set by the Baseball Charter. Shimoda said he asked Mizuno if the ball could be modified for 2013.

Norihito Kubota, who heads the company’s global equipment project team, said the composition of the rubber surrounding the ball’s core was changed to make it more lively.

“The rubber is a mixture of natural rubber and low-impact rubber,” Kubota said. “The actual percentage is a trade secret but we decreased the amount of low-impact rubber considerably.”

Shimoda said he decided not to announce the change to “prevent confusion.”

“I am deeply sorry to have caused trouble to the teams, the players and fans,” he said. “In retrospect, I should have announced the change. This is a matter I need to reflect on.”

NPB made the revelation in regards to a union demand on Tuesday for information about this year’s ball. NPB had previously denied that this year’s increase in home runs had anything to do with changes to the baseball.

The union argued that any changes to the ball represented a change to players’ working conditions and could represent a hardship to those whose performance-related bonuses are adversely affected.

“The players are our partners,” Kato said. “We could not give them inaccurate information.”

Shimoda admitted that NPB had asked Mizuno to keep a lid on the information and follow NPB’s official line that no changes had been made to the balls, which were switched out prior to the start of the season.

In April, the Mizuno responded to media requests by saying the increase in home runs was primarily at domed stadiums and due to foreign batters hitting so many home runs.

When asked why it was necessary to tell the truth to the players but acceptable to withhold the whole truth from the teams and the media, Shimoda was evasive.

“My decision has caused a lot of trouble. In hindsight, I would have done it differently.”