If there is no labor agreement by the end of Monday, the season will be shortened in 2022.
The season was supposed to start on March 31 but management maintained that the deadline was for a deal. Both sides are waiting for more time to force more major moves by the other, and players have not said whether they accept that timeframe.
The MLB made a declaration after another day of minor moves. Major League Baseball offered to increase the minimum salary by an additional $10,000 a year.
The minimum for this year has been raised to $640,000, with the figure rising by $10,000 each additional season of a five-year agreement.
The players want $775,000 in 2022, with $30,000 jumps each season.
The size of the bonus pool for pre-arbitration players was not moved.
The Yankees pitcher and the Mets pitcher were involved in the talks on the third day of bargaining.
Andrew Miller, a free-agent pitcher from the Yankees, was joined in the negotiations by Francisco Lindor, a catcher from the Astros. The eight members of the executive subcommittee are in charge of collective bargaining.
Texas infielder Marcus Semien and Boston pitcher James Paxton have not been seen during the talks at Roger Dean Stadium.
Scott Boras is the most powerful agent in baseball.
The teams have told the union they will not decrease revenue sharing and will not add new methods for players to accrue service time, which players said are needed to prevent teams from holding players back to delay free agency.