PHOENIX — Baseball’s commissioner, Rob Manfred, said Tuesday he expects no meaningful rule changes at the major league level for the 2017 season — largely because of resistance from the MLB Players Association — but vowed to continue pursuing strategies to speed up the pace of play in future seasons, even if that means ultimately imposing unilateral rule changes over the union’s objections.

“We have a disagreement about the need to push forward on these issues,” Manfred said in a news conference at the Arizona Biltmore Hotel. “. . . I have great respect for the labor relations process, [but] I have to admit I was disappointed we could not even get the MLBPA to agree to even a modest rule changes like [limiting] trips to the mound.”

Manfred’s comments came two days after union chief Tony Clark said the players were against most of the rule changes and argued the sport could increase the level of fans’ engagement with the sport through education instead of rule changes.

“I reject the notion we can educate fans to embrace the game as currently being played,” Manfred said.

Manfred said the labor agreement reached in December contains a two-year negotiating window for agreeing to rule changes. But while that process requires agreement from both sides to make changes in 2017, management retains the right to impose changes unilaterally in Year 2, should no agreement be reached.

“The idea that management has the right to make changes in its product, in this case the game on the field, is fundamental and well-recognized in labor laws,” Manfred said. “. . . Tony is more than within his rights to say right now he doesn’t want to move ahead with those rule changes. We will continue the process and will exercise the rights we negotiated under the basic agreement. Hopefully that process will reach an agreement. I want an agreement on these issues. But I’m also not prepared to walk away on this topic just because Tony’s not ready to move forward now.”

Manfred has been pushing strategies for speeding up the pace of play in baseball, citing fan studies suggesting games are too long and full of inaction. Among the ideas he sought for 2017 were limiting trips to the mound, installing a pitch clock to keep pitchers from stalling and replacing the four-pitch intentional walk with an automatic one.

“I’m glad the players love the game the way it is,” Manfred said. “We know based on fundamental research what our fans think of game. It’s in the players’ interest and in our interest to respond to what fans think of the game.”

Manfred said he does not have an ideal time-of-game goal in mind but rather is looking for ways to reduce “dead time” and increase ball-in-play action.

Among the proposals that drew outsized attention this winter was one that would place a runner on second base at the start of each extra half-inning. But Manfred said that was never intended to be used at the major league level and will only be implemented at the lowest levels of the minor leagues as an experiment.

“But as with everything,” he said, “you might learn something from the experiment.”

Also on Tuesday, Manfred rejected suggestions, made privately by some agents, that teams were guilty of colluding to tamp down free agent prices this winter. Two days earlier, Clark said he was having discussions with agents about those claims and failed to dismiss the suggestion outright.

“The free agent market was a free and open market,” Manfred said. “Markets go up, markets go down. It just depends on the quality of players and the needs of clubs . . . I think it’s unrealistic in today’s sports world that every free agent market is going to be a wild spree until the last guy signs.”

Manfred also reiterated his support of the World Baseball Classic, despite tepid interest in it domestically, and vowed it will not go away as long as he is commissioner.

“I think the key to the WBC’s success is to have the best possible rosters we can have. I think we made real progress this time around,” he said. “The U.S. is always going to be bigger challenge [to market the event] because people have Major League Baseball here. [But] a good performance by the U.S. team would certainly be helpful to the event here in the U.S.”