Representatives from Major League Baseball and the MLB Players Association held an informal meeting Thursday to resume talks amid baseball's work stoppage, multiple sources told ESPN.

MLB deputy commissioner Dan Halem and union attorney Bruce Meyer -- the lead negotiators for both parties -- were joined by league senior vice president Morgan Sword and MLBPA attorney Ian Penny, according to sources.

The New York-based meeting lasted 90 minutes, sources said, and covered the core issues that led MLB to cancel the first week of regular-season games Tuesday.

There was no indication as of Thursday afternoon when the sides planned to meet again. The MLBPA executive board was to hold a conference call later Thursday.

With owners and players unable to agree on a collective bargaining agreement to replace the previous deal that expired Dec. 1, MLB commissioner Rob Manfred canceled the first two series for each of the 30 teams, cutting each club's schedule from 162 games to likely 156 at most. A total of 91 games were erased.

After nine days of talks in Florida, negotiators headed home Wednesday after the breakdown at Manfred's Tuesday deadline for a deal to preserve Opening Day.

Baseball's ninth work stoppage was in its 92nd day Thursday and is the sport's first labor conflict to cause games to be canceled since the 1994-95 strike wiped out the World Series for the first time in 90 years.

Athletes from other major North American professional leagues have voiced their support for the MLBPA in recent days.

The NFL Players Association released a statement Thursday, emphasizing that it stands "in solidarity with our brothers at the MLBPA" and adding that "without the players, there is no game." The National Basketball Players Association praised the MLBPA for its "long history of sacrifice for the common good" in a statement Wednesday night.

More than pure numbers are a cause of the contention. Players have accused teams of widespread service-time manipulation and are seething over MLB's increased number of rebuilding clubs, which the union calls tanking.

Issues such as the size and format of the postseason also have become divisive, but the luxury tax may be the single most difficult issue. MLB proposed raising the tax threshold from $210 million to $220 million in each of the next three seasons, $224 million in 2025 and $230 million in 2026.

A higher threshold likely would lead to more spending by large-market teams such as the New York Yankees, Boston Red Sox and Los Angeles Dodgers.

Manfred cited a "payroll disparity problem" on Tuesday, saying a significantly increased tax threshold would "weaken the only mechanism in the agreement that's designed to promote some semblance of competitive balance."

Players are unhappy with how the tax system worked during the last labor contract, which included surtaxes to discourage high spending.

ESPN's Jesse Rogers, Jeff Passan and Marly Rivera and The Associated Press contributed to this report.