Good left-handed relievers should be cherished, and Aaron Bummer fits the bill in that regard. The Atlanta Braves picked him up in a trade in November 2023 and despite the fact that it took five players leaving in order for the Braves to bring him in, it ended up being a pretty lopsided trade in favor of the Braves. Bummer was expected to deliver solid production out of the bullpen and while he had to deal with tough luck and the relief corps variant of a lack of respect, he delivered the goods and then some. How acquiredThe Braves sent Michael Soroka, Jared Shuster, Nicky Lopez, Braden Shewmake and Riley Gowens to the White Sox in exchange for Aaron Bummer. The Braves already figured to have a good bullpen heading into the 2024 season and they were able to turn five players that they didnt regard all that highly and/or have a way of fitting onto the 2024roster into a southpaw reliever who could hopefully provide a real boost to their relief corps. What were the expectations?Again, it was expected that Bummer would come in and be a reliable lefty option coming out of the pen in whatever medium- or high-leverage situations A. J Minter didnt get. Bummer had a pair of fWAR seasons where he was worth at least 1. 0 in fWARand he was coming off of a season where he produced 0. 8 fWAR over 58 inningsSure enough, that happened again in 2024 but in this case it was a bit ridiculous. Bummer finished with a career-low full season FIP of 2. 23 and a FIP- of 57, which was nearly 30 points lower than his ERA-. His xFIP- was 63, so it definitely wasnt a fluke. Only 15 pitchers in 2024 had 50-plus innings and a bigger ERA-FIP gap than Bummer; Why am I putting this in the What went wrong? column? Because its really fun to imagine what it wouldve been like had he actually gotten things to go his way on a regular basis when the ball was put in play. Bummer ended up with a BABIP of Alex Dickerson Jersey. 386, which is pretty wild. In fact, that BABIP of. 386 was the worst among all qualified relievers in Major League Baseball in 2024. Yes, you read that right: He was rock bottom. Gregory Soto was the runner-up with a BABIP of. 371, which means Bummer was essentially in a league of his own when it came to BABIP going against you look at his Batting Average Against on each of his pitches in 2024 and compare it to the Expected Batting Average Against on those same pitches, its a bit wild to see the Savant Since BABIP is a bit of a crude measure, we can also tell you that among any reliever with 100 or more batters faced, Bummer had the sixth-widest gap between his xwOBA and wOBA, and five of those relievers faced 160 or fewer batters, compared to Bummers surrendered 61 hits on the year, which was the most of any pitcher in Atlantas bullpen, with Jesse Chavez coming up just one hit shy of tying Bummer in that regard. Despite giving up the most hits of anybody in the bullpen, he had more strikeouts and fewer innings pitchedthan Raisel Iglesias didreliever on the team other than Jesse Chavez, though Luke Jackson also ended up even lower after being acquired. The die seemed to be cast early on in his second appearance of the season, Bummer entered with a one-run lead and left with a two-run deficit thanks to: hard single, grounder through the infield, soft bloop over the infield, grounder through the took him a month to get back to steady higher-leverage work, but on June 9, he came in with the Braves already trailing and the bases loaded and allowed a first-pitch soft liner double to C. J. Abrams, and was basically banished to meaningless appearances thereafter. If you wanted to be charitable to the Braves and their decision-making, you could say that the reason they did this is because, deserved or not, the game ended up being blown when Bummer was pitching. He finished with six shutdowns and nine meltdowns; amid the 14 appearances that began with him entering the game in above-average leverage to any extent, he collected six shutdowns and had five meltdowns, which isnt really a ratio you want to see. Again, though, those meltdowns had little to do with his actual pitching. His FIPs in them? -2. 83, 0. 17, 1. 17essentially conspired to make sure that it wasnt a great season. 2025 OutlookWell, the Braves were presumably happywith what Aaron Bummer gave them in 2024 as he ended up signing a contract extension to stick around through the 2026 season. Considering Bummers body of work over the course of his career, its difficult to envision him having a serious downturn in performance in 2025. Who knows? Maybe his ERA will start looking like his FIP and if that happens then everybody in Braves Country going to be having the opposite of a bummer* whenever they see him pitch. As it is, though, he basically projects heading into his age-31 season the same way he did when the Braves acquired him a quite-good reliever. Even ZiPS is on board now!*I was not going this entire article without making a terrible joke. I know yall were all waiting on it.