NEW YORK -- Major League Baseball and its players' union reached an unprecedented agreement to discuss renegotiating their labour contract that has three seasons remaining. This is part of a deal that includes modest rule changes for 2020 and drops pitch clocks until 2022 at the earliest.

Players have been furious at slow free-agent markets during the first two offseasons of the five-year labour contract. The sides normally would start negotiations during spring training entering the agreement's final year. Management and the union agreed to discuss a renegotiation and extension of the current deal, set to expire on Dec. 1, 2021.

The agreement announced Thursday eliminates all trades from July 31 through the end of the season starting this year, though players who clear outright waivers can still be claimed and will be eligible for the post-season if they are in the organization before Sept. 1.

Mound visits without pitching changes will be cut from six to five. MLB intends to cut half-inning breaks to 2 minutes this year, down from 2:05 for most games and 2:25 for nationally televised games.