Major League Baseball is willing to loosen the regulations for the color of players' spikes.

Ben Zobrist, Kyle Schwarber and Steve Cishek wore black spikes in May despite a warning from Major League Baseball of violating a regulation requiring that at least 51 percent of the exterior of a player's shoes be the club's designated primary shoe color. For the Cubs, that color is blue.

"We recognize the need to allow players to be more demonstrative on the field," baseball Commissioner Rob Manfred said Tuesday at the All-Star Game.

Manfred said Deputy Commissioner Dan Halem had given the union "a proposed agreement that would substantially alter the rules respecting cleat colors and what could be on cleats."

Baseball, however, does want to maintain some sort of dress rules.

"What you don't want to do is get into a situation where the field becomes a billboard for any and all political messages," Manfred said. "The politicization of sport can be a very problematic thing."