NEW YORK — Major League Baseball imposed stricter limits on mound visits by players in an effort to speed games but decided against 20-second pitch clocks for 2018.

After more than a year of negotiations, the Major League Baseball Players Association refused to agree to the changes but also signed an agreement that it will not oppose the rules.

The amendments to the playing rules announced Monday include a general limit of six mound visits per nine-inning game without a pitching change, whether by a manager, coach or player.

To assuage players’ concerns about sign stealing, MLB will install new telephone lines from dugouts to video replay rooms. MLB said the lines will be monitored, and all conversations on the lines will be recorded.

MLB has the right to make playing rules changes absent an agreement with one year notice and made proposals during the 2016-17 offseason for a pitch clock and more restrictions on mound visits.

“I am pleased that we were able to reach an understanding with the players association,” Commissioner Rob Manfred said in a statement. “My strong preference is to continue to have ongoing dialogue with players on this topic to find mutually acceptable solutions.”

Union head Tony Clark noted the sides technically did not reach a deal.

“The focus on mound visits and/or the level of commitment on the other pieces simply didn’t focus enough attention on the areas the players wanted to address — so no agreement was reached,” he said in an email to the AP.

Until now, the only restriction on mound visits was a second visit to the same pitcher during an inning by a manager or coach resulted in an automatic pitching change.