(Jupiter, FL) -- Major League Baseball and the Players Association are continuing negotiations to end the league's current lockout. The sides met for a fourth straight day Thursday, though no progress was made toward agreeing on a new collective bargaining agreement. Talks are now on a time crunch as the sides effort to avoid delaying Opening Day, which is scheduled for March 31st. If the sides don't come to terms by Monday, the MLB has made it clear that any games missed won't be rescheduled. That would result in a shortened season for the league. The lockout first began on December 2nd.