IRVING, Texas — The future of the sport is unfolding in the conference rooms of a luxury hotel here.

On Monday and Tuesday, Major League Baseball officials and a handful of team owners met with players and players’ union officials at the Four Seasons Resort and Club Dallas at Las Colinas. Monday’s meeting lasted a couple of hours, while Tuesday’s sessions were both in the morning and afternoon.

The clock is ticking. At 11:59 p.m. Eastern on Wednesday, baseball’s foundation — the five-year collective bargaining agreement between the owners of the 30 M.L.B. teams and the players — expires. The document governs everything from the length of the season to roster sizes to the domestic violence policy to the sport’s economic structure.

The economic structure has been the biggest sticking point for years now and remains so as the sides negotiate. M.L.B. officials and the seven club owners who comprise the league’s labor policy committee came to Texas to bargain directly with the players during the union’s annual off-season executive board meetings. But if a deal cannot be struck by the C.B.A.’s expiration, a lockout that would freeze the entire sport is possibly looming.

M.L.B. has not had a work stoppage since the strike that prematurely ended the 1994 season, canceled that year’s World Series and bled into the next season. Players then successfully staved off the implementation of a salary cap, but the episode was damaging for the sport. There has been labor peace since and baseball has grown into an $11 billion a year industry, with superstar players continually breaking records for contract size.

Since the last C.B.A. was struck before the 2017 season, though, the union and players have become increasingly vocal about what they consider flaws in the system. That agreement is viewed as having further tilted the balance in the owners’ favor, with changes such as harder caps on international spending and stricter penalties for higher payrolls.

Players want a series of improvements including getting younger players (who are cheaper and have been relied upon more) compensated sooner in their careers, allowing players to reach salary arbitration and free agency sooner, and forcing teams to be more competitive through spending requirements.

Owners, on the other hand, believe M.L.B. players have the best deal in professional sports and point to this off-season’s free-agent spending as one bullet point in that argument. M.L.B. has also said it wants to improve the competitive balance among teams but has proposed different ways to accomplish that than the union. Among its proposals, some of which have been rejected: changes to the amateur draft order that could help prevent tanking, a club payroll floor along with a lower luxury tax threshold, overhauling the salary arbitration system, making free agency based on age and expanding the playoffs, which would net more revenue.

During this year’s World Series, M.L.B. Commissioner Rob Manfred and Tony Clark, the executive director of the M.L.B. Players Association, publicly expressed some optimism that a deal will be reached ahead of the deadline.

But the animosity and mistrust between owners and players has ratcheted up over the years. It came to a head last year during the bitter negotiations over the resumption of the 2020 season, which had been suspended during spring training by the coronavirus pandemic. The sides bickered for months and issued sharp statements.

This year has been different, as both groups vowed to learn from the lessons of last summer and have largely negotiated out of the public’s eye. Players, though, have been more resolute than in the past. The dispute last year united them and forced some of them to pay more attention to the economics of their sport. There are many negotiation hurdles and fraught labor relations to overcome by Wednesday.

At the owners’ meetings in Chicago in mid November, Manfred argued an off-season work stoppage was more palatable than one that hurt the season.

“I can’t believe there’s a single fan in the world who doesn’t understand that an off-season lockout that moves the process forward is different than a labor dispute that costs games,” he told reporters then. He added later, “We understand, I understand, that time is becoming an issue.”

If no new agreement is reached by late Wednesday night, M.L.B. owners could use a hammer immediately: a lockout that freezes all transactions. If that were to happen, team executives would not be allowed to talk to players, make major-league signings or swing trades.

Although lockouts have occurred in the four major men’s North American professional sports leagues in instances like this, they are not a requirement. Should M.L.B. and the union make progress in their negotiations in the waning hours, the owners could temporarily hold off on enacting a lockout.

On Tuesday morning, M.L.B. officials and owners such as Hal Steinbrenner of the Yankees, Mark Attanasio of the Milwaukee Brewers and John Henry of the Boston Red Sox emerged after more than 30 minutes from a meeting in which they heard a proposal from the union. They retreated to their hotel to talk but returned to the players’ hotel in the afternoon.

In a large conference room, union officials and a contingent of players (an estimated 60 were in town for the union meetings) huddled with M.L.B. officials and the owners for over 30 minutes.

Each side then broke off into their own conference rooms. At one point, St. Louis Cardinals pitcher Andrew Miller, a top union representative, and Bruce Meyer, the union’s lead negotiator, walked off with Dick Monfort, the Colorado Rockies’ owner and the chair of the league’s labor committee, and Dan Halem, M.L.B.’s lead negotiator.

After nearly an hour, the groups parted ways. M.L.B. officials and the owners got in their cars to leave, while the players returned to their rooms. What happens next is in their collective hands.