Baseball’s simmering labor battle, which informed the sport’s halting response to the coronavirus pandemic and led to an acutely shortened 2020 schedule, has complicated plans to launch the 2021 season, with one critical difference: With talks between MLB and the players’ union stalled, the default outcome this time is an on-time start to spring training and a full, 162-game season, as risky as that might be.

With roughly two weeks until spring training camps are scheduled to open, the MLB Players Association on Monday rejected a proposal MLB submitted over the weekend, calling for a one-month delay to spring training, a 154-game regular season (with players paid for 162), a designated hitter in both leagues and an expanded postseason wrapping up in the first week of November.

The union rejected MLB’s proposal without offering a counterproposal, saying in a statement that the players “will instead continue preparations for an on-time start to the 2021 season, and will accept MLB’s commitment to again direct its Clubs to prepare for an on-time start.”

In response, MLB issued a statement saying “we are moving forward and instructing our Clubs to report for an on-time start to Spring Training and the Championship Season, subject to reaching an agreement on health and safety protocols.”

MLB’s proposal was based largely on the recommendations of health officials and the belief that a delay — amid current, nationwide infection rates that dwarf those of last summer and fall — is baseball’s best hope for a successful season that includes in-person fans in greater numbers.

Logic might suggest a one-month delay to the season is warranted, with the lost weeks made up on the back end, allowing time for infection rates to decline and for the emerging vaccines to be distributed more widely, as well as the possibility of fans returning to stadiums in larger numbers deeper into the year.

However, as always, the animating force at work in baseball is not logic, but economics. For starters, MLB’s television network partners don’t want the postseason to extend past the first week of November, a reality that boxes baseball into a limited calendar. A compacted schedule, featuring fewer days off and more doubleheaders, increases the chances of widespread disruption if outbreaks occur.

For the players, the economic concerns are both short-term — making sure they are paid full salaries in 2021 after earning just 37 percent of full pay for the 60-game 2020 season (and having to fight the owners just to get that) — and long-term, reflecting their growing belief that MLB’s current economic model fosters anti-competitive behavior on the part of teams.

Although MLB’s proposal called for players to receive their full 2021 salaries, despite a schedule shortened by eight games, union officials were quick to point out the proposal did not guarantee those salaries. Instead, it gave Commissioner Rob Manfred wide powers to postpone and cancel games, or even halt the season amid outbreaks — powers the union views with unease.

MLB’s proposal, the union said in its statement, “offers no salary or service time protections in the event of further delays, interruptions, or cancellation of the season.”

MLB, though, sees the commissioner’s powers as necessary to deal with the many unknowns and contingencies inherent in attempting to play through a pandemic — at a time when the vaccine rollout has been slower than hoped and variants of the virus are emerging — but the mission would be to play as many games as possible. The proposal also outlines specific circumstances under which Manfred could cancel games, including government restrictions on gatherings and travel, and issues of competitive integrity.

Last year, after the sides were unable to reach an agreement, Manfred implemented a 60-game season, with players receiving prorated shares of their full salaries. Although the season nearly came apart in late July amid outbreaks on the Miami Marlins and St. Louis Cardinals, ultimately just two games were lost all season, with 28 of baseball’s 30 teams completing 60 games, and the other two, the Cardinals and Detroit Tigers, playing 58.

“Players know first-hand the efforts that were required to complete the abbreviated 2020 season,” the union’s statement said, “and we appreciate that significant challenges lie ahead.”

MLB officials have claimed its teams lost billions in revenue from the shortened season without fans — underscoring the importance of playing as many games as possible with as many fans as possible in the stands in 2021 — but union officials are skeptical of those claims.

MLB’s proposal for an expanded, 14-team postseason in 2021 — down from the 16-team field of 2020 but up from 10 teams under the usual format — presents another point of contention. MLB, seeing the potential revenue gains from an expanded postseason, has offered to give the players the universal DH in exchange.

However, the union sees expanded playoffs as problematic on a fundamental, economic level — disincentivizing spending on the part of owners, and thus damaging free agency, because a team would need fewer wins to reach the postseason — and thus too large of a bargaining chip to give away for a rule change, the universal DH, that both sides want.

The lack of clarity on the DH for 2021 has hampered the roster-building efforts of some National League teams and damaged the free agent markets for sluggers such as Nelson Cruz and Marcell Ozuna, whose marketability would be enhanced significantly if all 30 teams needed a DH.

The flurry of discussions came at the end of a winter of sputtering, intermittent talks between the sides, and at a time when equipment trucks are arriving at spring training camps in Arizona and Florida, and when players, especially pitchers, have paid for spring training rentals and ramped up their throwing programs in anticipation of an on-time start.

MLB’s proposal for a delay would have required those players to dial back their preparation and then start up again for what would be a March 22 opening of camps, with the regular season scheduled to begin April 28.

Arizona has the nation’s highest rate of new coronavirus infections, but officials there have said they expect case numbers to drop significantly over the next month or so — projections that suggest a delay makes sense.

The players, however, point to the fact that the NFL has navigated its season, and the NBA and NHL are well into theirs — with all three leagues permitting fans at varying levels.

In the absence of an agreement, MLB and the players are set to default to their previously agreed upon schedule, with spring training camps opening in mid-February, exhibition games starting Feb. 27 and Opening Day slated for April 1.

But that doesn’t mean the vitriol will dissipate. If anything, without an agreement to dictate the handling of specific issues, Manfred’s actions will be under even more scrutiny, while the possibility increases of a doomsday scenario in which the season has to be shut down, leading to a massive fight over players’ salaries.