Major League Baseball is prepared to scuttle the implementation of a pitch clock until at least 2022 as part of a wide-ranging proposal to the MLB Players Association that would include the ability to implement a three-batter-minimum rule for pitchers and roster-size changes in 2020, sources familiar with the plan told ESPN.

MLB also is proposing limitations on position players' usage as pitchers, getting rid of the waiver trading period, further cutting mound visits and potentially shortening inning breaks, sources said.

The proposal, sent by the league on Tuesday, is the latest in a back-and-forth bargaining session centered around the league's unilateral ability to implement a 20-second pitch clock. Amid tension between the parties stemming from a free-agent market that players have found unsatisfactory, the league, which is testing the pitch clock in spring training games, offered not to revisit the issue until after the 2021 expiration of the current collective bargaining agreement as part of a broader set of rule changes.

A number of the proposals from the league dovetail with past suggestions from the union, according to sources, lending credence to the notion that an agreement can be reached with minimal animus.

The most controversial aspect is the three-batter-minimum rule for pitchers. The desire to increase the pace and speed of games could be aided by the rule, which aims to end the carousel of relief pitchers that has become so commonplace late in games. Under the proposal, the league would have the right to implement the rule -- which has a caveat for injured pitchers -- in 2020.

That year, rosters also would be expanded by one to 26 players, with a maximum of 13 pitchers, according to sources. While the league's proposal includes a mandated 28-man roster with a 14-pitcher cap in September, the union has chafed at limiting roster sizes when teams currently can use as many as 40 players in the season's final month.

MLB took the union's suggestion of a single trade deadline before the All-Star break and countered by keeping the current July 31 deadline in place but eliminating trades in August for players who clear waivers, sources said. The league did, in the proposal, agree to abide by the union's suggestion for reduced mound visits -- from six to five in 2019 and five to four in 2020.

The use of position players as pitchers would have rules attached to it, sources said. Each player at the beginning of a season would be designated a pitcher or position player, except in cases where a player is deemed a two-way player (with 20 major league innings pitched and 20 starts at a position, including designated hitter, with at least three plate appearances). Position players could pitch only after the ninth inning or following the sixth inning in games in which their team trails by at least seven runs.

The league proposed having the right in 2019 to shorten inning breaks from 2 minutes, 5 seconds to 1 minute, 55 seconds in locally broadcast games, in addition to shaving 30 seconds off the current 2-minute, 25-second breaks in national games, according to sources. If agreed upon, the league would begin testing the change this spring before implementing it.

Also included is a joint study of the strike zone and mound height and distance, according to sources, another spot in which the parties' thinking coincides. MLB, in a partnership with the Atlantic League, plans on using the independent league this year to begin testing an automated strike zone and mound distance farther than 60 feet, 6 inches, according to a Baseball America report.

Other proposals by the league include: