Although the Major League Baseball Players Association (MLBPA) informed the league that players will comply with commissioner Rob Manfred's imposed outline for a 60-game 2020 season, there are still unresolved concerns relating to individual player contracts.

The two sides spent the weekend negotiating an agreement that would determine how vesting options, roster and retention bonuses, and other contract clauses would be work in the abbreviated 2020 season, according to The Athletic's Ken Rosenthal. As of Sunday night, MLB and the union were close to an official deal, Rosenthal adds:

The conversations might have been necessary even if the sides had reached a settlement last week, but now time is of the essence, with players starting to get tested for COVID-19 and reporting to training camps by Wednesday. A failure to reach agreement could spark additional material for grievances, but sources suggested Sunday night that a deal was within reach.

Rosenthal says that the specific player contract issues that have come up recently have surprised and upset some players. Some player agents were not fully advised by the MLBPA of these unanswered questions when the two sides reached their March agreement.

None of the contract topics were addressed in any of the proposals exchanged between the two sides, and many could have been resolved if the two had actually reached a new deal after their March agreement, per Rosenthal. Things are made more complicated with specific contract issues, like those that rely on reaching a set number of games pitched or plate appearances, since there is still the chance that the 2020 season could be canceled altogether due to health concerns regarding the coronavirus.

Rosenthal lays out one of the issues the two sides are currently debating; how to handle vesting options for players. Take this example in Cardinals reliever and MLBPA executive committee member Andrew Miller, who is one of the players with a vesting option for 2021:

Cardinals reliever Andrew Miller, a member of the union's eight-man executive sub-committee, is one of the players with a vesting option for 2021 that is in dispute. MLB, according to sources on the players side, originally wanted to pro-rate the amount of Miller's option from $12 million to $4.44 million, using the same formula by which it will pay players this season. The league later indicated the vesting options for 2021 might retain their full values, but because of the shortened schedule, differences remain over the number of games in which Miller and others will need to appear to guarantee their '21 salaries.

Miller's contract states that his vesting option will become guaranteed if he pitches in 110 games in the 2019 and '20 seasons combined. He appeared in 73 games last season, which would have left him 37 games short of the total, or 23 percent of a 162-game season. The league might argue that his new target should be 23 percent of 60: 14 games. Miller might counter with different math, noting the league will play 222 of a possible 324 games in 2019-20. The corresponding percentage of 110 games is 75, just two more than where Miller currently stands.

Further complicating the equation: The possibility that commissioner Rob Manfred might choose to further shorten or cancel the season because of issues stemming from COVID-19. The parties, then, need to decide how many games someone like Miller would need to pitch if the season ended up consisting of say, 40 games.

After finally determining the length of the season, prorated salaries and the health and safety protocols amid the coronavirus pandemic, it appears the league and MLBPA still have more to figure out before the season begins. Players are set report for another version of "spring" training on July 1, and the regular season will start either July 23 or 24, the league announced.