By Ronald Blum

AP Baseball Writer

NEW YORK (AP) — Major League Baseball and its players are discussing bold changes to spark the sport that include a three-batter minimum before a pitching change except at the start of an inning, a single trade deadline set before the All-Star break and expanded rosters.

The union renewed its push to extend the designated hitter to the National League, suggested amateur draft incentives for winning records and penalties for losing records and proposed a change in service-time rules that would lead to faster free agency for top rookies held in the minor leagues early in the season. Management proposed expanding minimum time on the disabled list and optional assignments to the minor leagues to 15 days.

The talks are an expansion of the ones last offseason in which management threatened to implement a pitch clock, then backed off but did institute limits on mound visits without pitching changes. Management made its proposal on Jan. 14, the union responded last Friday and discussions are ongoing.

Details were disclosed to The Associated Press by people familiar with the negotiations who spoke on condition of anonymity because no statements were authorized. Aspects of the proposals were first reported by The Athletic.

Management is concerned about a drop in offense that saw strikeouts exceed hits for the first time last year and the big league batting average drop to its lowest level since 1972. In a season that included an unusually cold and wet April, average attendance dropped for the third straight season and fell below 30,000 for the first time since 2003.

Some of the most interesting changes appear likely to be put off until 2020 at the earliest.

RELIEF PITCHERS

Management proposed that a team not be allowed to bring in a reliever until the previous pitcher has faced three batters or an inning ends. There were 1,145 one-batter outings last season, according to the Elias Sports Bureau, up from 1,119 the previous year but down from 1,182 in 2016. The change would have an impact on the use of “openers” for a few batters, a move pioneered by Tampa Bay manager Kevin Cash and emulated by Milwaukee manager Craig Counsell in Game 5 of the NL Championship Series, when he removed left-handed starter Wade Miley after one batter and replaced him with right-hander Brandon Woodruff.

Players countered the change should start in the minor leagues this year and reach the majors in 2020.

DESIGNATED HITTER

The DH has been used in the AL since 1973, but the NL has never adopted the rule and Commissioner Rob Manfred has said he supports the status quo. The union proposed the DH start being used in the NL this year, but management in the past has considered the DH an economic issue, and Manfred has said that economic changes must wait for negotiations for a new labor contract that would start ahead of the 2022 season.

PITCH CLOCKS

Management again has proposed a pitch clock, and the union countered with limitations on its use.

MOUND VISITS WITHOUT PITCHING CHANGES

A limit of six began last season, and management wants to lower that to four this season and three in 2020. The union countered with five this year and, if the average time of a nine-inning game is longer this year than last, then four in 2020.

TRADE DEADLINE

Players proposed a single trade deadline be instituted before the All-Star break to keep teams from dealing veterans when the clubs conclude their chances of a playoff berth have dwindled. The deadline for trades without waivers was June 15 from 1923 through 1985 and has been July 31 since. Players who clear waivers can be dealt after the deadline, but they must be in an organization by Aug. 31 to be eligible for the postseason.

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ROSTER SIZE

Many have criticized the roster rules, which generally allow a team 25 active players through Aug. 31 and then 40 until the end of the season. Management proposed allowing a 26-man roster, including a 12-pitcher maximum, through Aug. 31, and then up to 28 for the rest of the season. The union countered that each team should be required to have 28 active from Sept. 1 on and that there be a supplemental roster of four players after the Triple-A postseason ends. No starting pitchers would be allowed on the supplemental roster, and at least two of the four would have to be position players.

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ANTI-TANKING

Concerned that teams with small or no playoff chances put less of an emphasis on winning to get higher selections in the amateur draft, the union proposed that a team with 90 or more losses in consecutive years have its highest selection in the next amateur draft dropped 15 slots and lose $2 million in international signing bonus pool allocation. A team with 90 or more losses in three straight years would drop 20 slots and lose $3 million in allocation.

Clubs that reach the postseason would be awarded additional draft picks in the competitive balance rounds.

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SERVICE TIME

A player in his debut season or with less than 30 days of major league service in the previous season would be credited with a full year of major league service if he finishes among the top three in voting for Rookie of the Year, Cy Young Award, MVP or Rivera/Hoffman reliever award; he wins World Series or League Championship Series MVP; or he is among the top three in Wins Above Replacement, or WAR, defined by the average of the Fangraphs and Baseball Reference calculations. Currently, 172 days during the 186-day season are needed to be credited for a year of major league service. The Chicago Cubs called up Kris Bryant in 2015 to leave him with exactly 171 days, sparking a grievance that remains unresolved.

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DISABLED LIST/OPTIONAL ASSIGNMENTS

Management proposed that the shortest disabled list increase from 10 days to 15, its minimum before 2017, and the minimum time before an optioned player can be recalled from the minors also increase from 10 to 15 — keeping the exception that the limit does not apply when replacing a player who is placed on the DL. Concerned about service time, the union is not yet conformable with that plan.

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TWO-SPORT ATHLETES

Worried baseball may lose athletes such as Oakland outfielder Kyler Murray, the Heisman Trophy-winning quarterback, players proposed two-sport athletes be able to sign major league contracts. Since 2012, all amateur free agents must sign minor league contracts.

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STARTING EXTRA INNINGS WITH A RUNNER ON SECOND BASE

Players are generally amenable to management’s proposal to start the 10th and subsequent innings of spring training games and the All-Star Game with a runner on second, although in the All-Star Game they want a player who already has left the game to be eligible to be one of those runners.

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STUDY ON LOWERING PITCHER’S MOUND

The pitcher’s mound was dropped from 15 inches to 10 for the 1969 season, and management wants to establish a committee to study whether it should be lowered again. The union wants the committee to include active players.

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INNING BREAKS

Players are willing discuss whether inning breaks can be shortened. Among the ideas suggested include using split screens that include commercials on broadcasts at the start of half-innings.

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EXPANDED PLAYOFFS AND REALIGNMENT

Players are willing to discuss.

MICROPHONES

Players propose better fan engagement by allowing additional broadcast microphones on players, possibly including two-way microphones.