Only three more weeks remain in the MLB regular season and the postseason races are heating up. The Braves trail the Mets by only half a game in the National League East and the White Sox are just three back of the Guardians in the American League Central. The AL wild-card teams have separated from the pack, with the Blue Jays, Rays and Mariners heading toward the playoffs, but the top spot — and home-field advantage in the first round — is up for grabs, as the three teams entered Wednesday tied in the loss column. In the NL wild-card race, the Brewers have won five of their last six and trail the Padres by two games. The Phillies are 3 1/2 games up on Milwaukee (and own the tiebreaker), but they still have to face the Braves seven times, the Blue Jays twice and the Astros three times, so their schedule is not easy.

Playoff spots, home-field advantage and first-round byes are at stake. Here are some of the key players who need to step up in these tight races to help their teams over the next 21 days.

 

NL EAST RACE

Mets — 1B Pete Alonso

Alonso has been the Mets’ MVP all season long, slashing .268/.344/.505 with 24 doubles, 34 home runs and an NL-leading 110 RBIs. However, in the last 30 days he’s been relatively quiet, hitting .226 with seven extra-base hits in 27 games and 106 at-bats. To win the NL East and claim a valuable first-round bye, the Mets need Alonso to perform like the impact player he is over the final three weeks. The good news for New York: In his last seven games, Alonso has picked it up, batting .345/.387/.586.

Braves — RF Ronald Acuña Jr.

Acuña has been a disappointment this season in his return from ACL surgery a year ago, but thanks to the production of rookies Michael Harris II and Vaughn Grissom, the pressure on Acuña to perform has lessened. But as the Braves try to edge the Mets for the division crown, they need more from their superstar right fielder. Over the last 15 games, Acuña has batted .258 with a .310 on-base percentage and just one home run. However, he has stolen three bases in as many attempts during that span. Acuña’s base-stealing ability will be key down the stretch in helping the Braves batters after him get more fastballs to hit.

 

AL CENTRAL RACE

Guardians — their lineup, from top to bottom

The Guardians’ pitching staff is doing everything possible to lead them to a surprising AL Central title. Over the last 30 days, their team ERA is 2.65, third best in baseball. However, their offense has struggled during that span, ranking 29th in the majors with only 3.25 runs scored per game. To hold off the White Sox, the Guardians need their lineup to start producing. In the last 30 days, only Oscar Gonzalez (five home runs) and José Ramírez (four) have hit more than two long balls. Cleveland hitters have been working the count and getting on base but they have not been able to string together hits, which has become a late-season problem, especially when they’re not hitting for power. (The Guardians rank last in MLB with 16 homers in the last 30 days.) Down the stretch, the Guardians need their two position-player All-Stars, Ramírez and Andrés Giménez, to deliver at the plate, but they also need production from throughout the lineup, along with their elite pitching and defense, to hold off the White Sox, whom they face four more times.

 

White Sox — RHP Lucas Giolito

The White Sox are coming on strong offensively, thanks in part to the bats of Eloy Jiménez and Elvis Andrus, who have combined for 11 home runs and 33 RBIs over their last 15 games. Four of their hitters — Jiménez, Andrus, José Abreu and AJ Pollock — have batted over .340 and posted a .390 OBP or higher in the last 15 days. However, the key for the White Sox during the stretch run might be Giolito, who has struggled to match his rotation mates this year. Giolito’s numbers have deteriorated since last season, especially after the All-Star break, as he’s posted a 6.04 ERA and a 1.638 WHIP in the second half. They need him to turn things around in his final starts of the regular season.