By James Carney
The 2021 Atlanta Braves did not get off to a very impressive or memorable start to their season. They hovered around .500 throughout the majority of the first half and on June 30th sat at fourth in the NL East with a 37-41 record, and a 15% chance to make the playoffs. The Braves’ postseason prospects for 2021 got even worse when, on July 10, their star right fielder Ronald Acuña Jr tore his ACL and was ruled out for the season. Before his injury, Acuña was slashing .283/.394/.596 with a 155 OPS+ as a prime MVP candidate, and the floundering Braves without their superstar seemed destined for a disappointing finish to 2021. Yet, in November, the Braves were the team hoisting the championship trophy as the World Champions. What mid-season changes did the Braves make to execute this impressive turnaround?
Acuña’s injury wasn’t the only issue for the Braves outfield in the early part of the 2021 season. They lost their biggest offseason acquisition and 2020 Silver Slugger winner Marcell Ozuna in May to a finger injury (and later for the season to a domestic violence arrest). This left them with big holes to fill in both left and right field. On July 11, the Braves rolled out a starting outfield of Ehire Adrianza, Guillermo Heredia, and Orlando Arcia, three players who finished the year with an OPS+ of 90, 75, and 63 respectively. With an OPS+ of 100 being league average, the Braves were getting far below standard production from this trio. Needing lots of offensive help for their banged-up outfield, the Braves acquired Joc Pederson from the Cubs on July 15. They followed that up with a big trade deadline day, acquiring Adam Duvall from the Marlins, Eddie Rosario from the Indians, and Jorge Soler from the Royals all on July 30. While these players seemed to have been struggling in the first half of their seasons, the Braves were banking on them returning to their peak form and filling in down the stretch. These four outfielders did just that and were key to the Braves’ turnaround and playoff push and defined their magical playoff run. Rosario and Soler in particular greatly benefited from the change in scenery and had extremely impressive turnarounds in their second halves. Rosario went from slashing .254/.296/.389 with the Indians to .271/.330/.573 with Atlanta, while Soler went from an abysmal .192/.288/.370 to .269/.358/.524 after the deadline. In terms of wOBA,Soler’s .287 in games before July 30 would have him ranked 284th out of 391 qualified hitters (min 250 Plate Appearances) while his .380 post-deadline had him at 35th. Rosario rose even further, going from 266th at .294 to 13th at .407 after joining the Braves. Those numbers are impressive but are dwarfed by their postseason performances. Rosario performed incredibly in the NLCS against the mighty Dodgers, reaching base in 17 of his 28 plate appearances, hitting 3 home runs, and posting an astronomical 1.040 slugging percentage. He became the fifth player to record at least 14 hits in a playoff series and claimed NLCS MVP honors. Soler missed most of the NLCS after testing positive for COVID but unleashed his power on the Astros in the World Series, hitting 3 clutch home runs, and earning the World Series MVP. Soler slugged .800 and joined an impressive list of players to hit 3+ go-ahead home runs in a World Series, becoming one of six along with the likes of Babe Ruth and Lou Gehrig. In terms of cWPA, a statistic that calculates the percentage of a probability of a Championship that a single player adds, Soler added 7.56% percent to the Braves’ championship odds in Game 4 and a whopping 15% in Game 6, firmly leaving his mark on the 2021 season.
The Braves made a serious defensive change mid-2021, opting to employ the shift far more often in the second half of the season. The Braves in recent years have been one of the lowest shifting teams in baseball, and from 2019 through April of the 2021 season no team shifted less than the Braves. However, needing to make a change, after May 19 the Braves flipped their policy and became one of the most frequently shifting teams with the third-highest rate in baseball. The flip before and after May 19 was drastic, as the Braves went from shifting on 10.6% of pitches all the way up to 46.5%. There aren’t a ton of defensive metrics to measure the success of this change, but one we can use is BABIP against, which measures the Batting Average of Balls in Play for your opponent. This stat does not solely rely on defense, as quality of contact is oftentimes determined by the pitching, but over large sample sizes it can be a good metric to measure defensive success. In games before May 19, Braves’ opponents hit .305 on balls in play, good for fourth-most in the league. After the 19th, BABIP against Atlanta dropped to .275, the second lowest in baseball. Shifting has remained a controversial topic in baseball as many have called for its restriction or removal from the game, but embracing the shift certainly helped out the Braves defensively in 2021.
Two young breakouts on the Braves each won their first Silver Slugger awards this year. Third baseman Austin Riley and starting pitcher Max Fried both took home the award for best hitter in the National League at their respective positions. Riley made his debut in 2019 and didn’t make much of an impact in his rookie year, finishing with a -.03 bWAR and an 86 OPS+. His 2020 pandemic shortened season didn’t fare much better, as he again finished as a below-average hitter with an 86 OPS+. Riley flipped a switch in 2021, becoming a cornerstone of the 2021 Braves. Riley provided stability at third base all year, playing in 160 of 162 games with a .303/367/.531 and an OPS+ of 132. His breakout earned him a 7th place finish in MVP voting along with Silver Slugger award. Fried, similarly to Riley, had an unimpressive 2019, finishing with a 4.06 ERA, 1.334 WHIP, and 0.7 bWAR in 30 starts. Fried then had one of the most impressive MLB seasons in 2020, finishing with a 7-0 record, 2.25 ERA, 1.089 WHIP, and a fifth place Cy Young Award finish. He continued this success into 2021, lowering his WHIP to 1.087 and maintaining a low ERA of 3.04. Fried has also contributed significantly with his glove and his bat, taking home his second consecutive Golden Glove as well as the Silver Slugger award for NL pitchers. These two young stars, along with Acuña, set up Atlanta for years of continued success.
These factors are not the only ones that led to their World Series in 2021, as first baseman and 2020 NL MVP Freddie Freeman and 2021 Silver Slugger winning second baseman Ozzie Albies played a huge role in the success. The Braves’ bullpen also came up with consistent clutch performances throughout the postseason. However, the factors mentioned helped make the Braves unique in their success and helped them become the unlikely victor of the 2021 MLB season.
 Slash line consists of Batting Average, On Base Percentage, and Slugging Percentage (Total Bases/ABs)
 OPS+ is a league-standardized OPS measure. OPS is OBP + Slugging Percentage and is generally used to determine how good a hitter is. OPS+ puts each players’ OPS in a scale where 100 is league average. League leaders in OPS+ tend to sit around 160-190.
 wOBA, or weighted On Base Average, is an advanced stat that measures a player’s overall contributions per plate appearance.
 WAR, or Wins Above Replacement is an-uber complicated statistic that evaluates a player’s total value to a team. A war of 0 means a player was replacement-level, and league leaders tend to sit around 8-10 war. bWAR is WAR calculated by Baseball Reference. The other WAR used is fWAR, WAR calculated by Fangraphs.
 WHIP is Walks and Hits divided by innings Pitched