Whose playoff odds have changed the most?

Saturday marked not only the start of May but also one month since Opening Day, so it seems like a great time to take stock of how much things have changed around the Majors.

There may be five months left in this season, but remember, the games in April count the same as the games in September.

Based on FanGraphs’ playoff odds, these are the clubs whose postseason chances changed the most from Opening Day through the end of April. (Stats below are through Friday.)

Biggest risers

Brewers: +26.8 (42.2% to 69%)
Milwaukee’s offense has averaged just 3.96 runs per game with the worst OPS (.666) in the National League, but a lights-out pitching staff has carried the club to a 16-10 record. While Corbin Burnes has received much of the attention for his 1.53 ERA and 49-to-0 K/BB ratio through 29 1/3 innings, Brandon Woodruff (1.55 ERA, 10.6 K/9) and Freddy Peralta (2.25 ERA, 14.5 K/9) have been excellent in their own right. In the bullpen, Josh Hader has been as electric as ever closing out games, going 7-for-7 in save chances and allowing only one run with 19 K’s in 9 2/3 innings.

Given less than a 45% chance of reaching the postseason on Opening Day, the Brewers are now close to 70% -- by far the best odds in the NL Central.

Red Sox: +19.8 (38.9% to 58.7%)
Coming off a last-place finish in 2020, the Red Sox brought manager Alex Cora back into the fold but otherwise refrained from making wholesale changes in the offseason. With much of the same personnel, the club entered Saturday with a 3 1/2-game lead in the AL East.

Led by a resurgent J.D. Martinez (nine homers, 1.175 OPS), Boston’s offense owns the highest OPS (.759) in the AL. More importantly, its pitching has improved significantly, ranking third in the AL in ERA (3.55) after finishing 14th with a 5.58 mark in 2020. Eduardo Rodriguez’s return from a year-long absence and Nick Pivetta's strong start have boosted the rotation, and new bullpen additions Garrett Whitlock, Matt Andriese, Hirokazu Sawamura and Adam Ottavino have combined to allow 10 earned runs in 46 2/3 innings (1.93 ERA). With a 17-10 record, Boston now has the fourth-best postseason odds of any AL team.

White Sox: +18.7 (48% to 66.7%)
The White Sox were a popular preseason pick to win the AL Central, but FanGraphs put their playoff odds below 50% on Opening Day. Chicago’s big jump may have more to do with the Twins’ struggles (more on Minnesota later) than its own success, although the Sox have gone 14-11 with the Majors’ third-best run differential (+29).

The club has gotten strong performances from unexpected sources -- most notably, Yermín Mercedes, Carlos Rodón and Michael Kopech. Mercedes, a 28-year-old who had one big league plate appearance prior to 2021, finished April as the Major League leader in hits. Rodón tossed a no-hitter and went 4-0 with a 0.72 ERA in his first four starts. And Kopech has returned from a two-year absence to record a 1.72 ERA and a 15.5 K/9 rate in six appearances (two starts). The trio has helped keep Chicago on track despite losing Eloy Jiménez to a torn pectoral muscle and getting a combined -0.6 Baseball-Reference wins above replacement from reigning AL MVP José Abreu, Yasmani Grandal, Lucas Giolito, Dallas Keuchel and Liam Hendriks.

Royals: +11.8 (8.9% to 20.7%)
The Royals set themselves up for improvement with an active offseason, but even the most optimistic Kansas City supporters couldn’t have expected this. The club posted MLB’s second-highest winning percentage (.625) in April, going 15-9 and bumping its postseason odds north of 20%. Danny Duffy, Brady Singer and Jakob Junis have been terrific in the rotation, and six relievers have recorded at least one save for the club, which has gone 6-1 in one-run games.

What remains to be seen is whether this team has staying power. The Royals have a negative run differential (-2) and their offense has hit the fewest homers (22) in the AL, with Carlos Santana and Salvador Perez combining for half of the club’s total.

Giants: +10.7 (5.7% to 16.4%)
San Francisco re-signed Kevin Gausman with the $18.9 million qualifying offer and brought in Anthony DeSclafani, Aaron Sanchez and Alex Wood for a total of $15 million on one-year deals in the offseason. Those moves have given the Giants one of the most effective rotations in the Majors, as Gausman, DeSclafani, Sanchez and Wood have combined to go 7-1 with a 1.87 ERA in 18 starts. Meanwhile, Buster Posey and Evan Longoria have turned back the clock at the plate, and the Giants are in first place with a 16-10 record.

So why haven’t their playoff odds improved more? Because the Giants still share the NL West with the Dodgers and Padres. While San Francisco has a hold on first place now, FanGraphs puts Los Angeles' playoff odds at 98.6% and San Diego's at 94.7%.

Biggest fallers

Twins: -31.9 (63.3% to 31.4%)
Minnesota’s season hasn’t been without its positives. The Byron Buxton breakout is upon us, Nelson Cruz continues to defy Father Time and José Berríos, Michael Pineda and J.A. Happ have been solid. Overall, though, the Twins have put themselves in a tough spot with their 9-15 start.

Kenta Maeda (6.56 ERA) is the biggest concern for Minnesota, followed closely by its bullpen, which has the fifth-worst ERA (4.59) in the Majors and has contributed to the team's 2-6 record in one-run games and 0-5 mark in extra innings.

Braves: -19 (63.8% to 44.8%)
After three straight NL East titles, FanGraphs put the Braves' playoff odds at 63.8% on Opening Day. With a 12-14 record in April, Atlanta has dropped below 45%. The Braves have the worst ERA in the NL at 4.97, and Max Fried, Michael Soroka and Chris Martin are all on the IL.

Fortunately for the Braves, none of the other NL East teams has distanced itself from the pack. Moreover, none of the other NL East teams has Ronald Acuña Jr., the NL MVP Award frontrunner after one month.

Cubs: -13.4 (22.9% to 9.5%)
The Cubs looked to be heating up when they went 5-1 and outscored their opponents 55-27 from April 17-23, but they’ve followed that up with a 1-6 stretch to end the month. Chicago has the worst rotation ERA (5.81) in the NL by two-thirds of a run, and it has been shut out five times, tied for the most in the Majors.

Even Kris Bryant’s strong rebound season (1.078 OPS) might not be enough to save the Cubs, whose postseason odds have dropped below 10%.

Rays: -12.2 (26.6% to 14.4%)
The Rays were two wins away from a World Series title in 2020, but FanGraphs gave them just a 26.6% chance of getting back to the playoffs at the beginning of this season, and Tampa Bay’s odds have dropped after a 13-14 start.

Tyler Glasnow is a stud atop the rotation, and the club continues to unearth bullpen gems, but the injuries are starting to pile up. Joey Wendle has been the team’s most productive hitter, meanwhile. No disrespect to Wendle, but that’s probably not a good sign.

Yankees: -10.8 (91.3% to 80.5%)
If anything was going to sink the Yankees this season, it was expected to be their pitching. But as April came to a close, New York was leading the AL in ERA (3.09) and strikeouts (276). It’s been their hitting that has held back the Bronx Bombers, who rank among the worst MLB teams in runs scored despite pacing the AL in homers (37).

But even with their 12-14 record, FanGraphs gives the Yankees the best playoff odds of any AL team.