PHOENIX — Commissioner Rob Manfred says new rules intended to speed up the pace of games are aimed at luring younger fans to baseball.

Manfred, speaking publicly on the changes for the first time since they were announced last Friday, said the rules are a “measured” approach worked out with the players’ association.

This season, batters will be required to have one foot in the batter’s box and pitchers and batters will be required to be ready to go at the conclusion of television commercials.

“The issue of attracting a younger audience and a pace of game is related,” he said.

Manfred said he has four children in their 20s.

“I have a passing familiarity with that generation,” he said, “and one thing I can say for sure is their attention span seems to be shorter than the rest of ours.”

Last season, the average length of a major league game was a record 3 hours, 2 minutes.

“I certainly want to reverse the trend of increasing the length of the game,” Manfred said, “and I’m really intent on the idea that we’re going to have an average game time that’s going to start with a `two’ next year as opposed to a `three.”’

The commissioner spoke at a news conference on spring training media day, an event that draws the managers and general managers from the 15 clubs that train in Arizona.

Any rules changes have to be done with the cooperation of the players’ association, Manfred said.

“I talked with (players union executive director) Tony Clark on Thursday, the night before the changes were announced,” Manfred said. “I had a very positive conversation with Tony. We began these discussions with a conceptual understanding between Tony and me that we were going to proceed with caution on pace of the game.”

He said they wanted to make sure nothing was done to “change the way the game is played.”