A bit of a dark horse inclusion on this list, but I believe what Robert Garcia has provided to the Nationals this final stretch of the season should be recognized.
Claimed off waivers from the Miami Marlins on August 1st, Garcia has now appeared in 24 games for the Nationals, pitching to a 3.69 ERA with a 1.14 WHIP. While they are not spectacular numbers, Garcia has found himself in several tight spots with the struggles of both the Nationals' starting rotation and bullpen as of late and has performed well. Bullpen volatility is well documented in baseball, and Garcia is far from a proven commodity, but he has impressed during his brief time with the team.
I am including Garcia on this list for two reasons beyond his good ERA and WHIP: he is a left handed reliever and I do not trust Jose A. Ferrer yet. Think about how desperately the Nationals have needed a left handed reliever in the past couple of seasons. Anthony Banda made the team out of Spring Training due to necessity, not necessarily merit from a strong Spring Training performance. Last season, the Nationals ran with an all Right Handed bullpen for a time before bringing back Sean Doolittle for 5 innings prior to his injury that effectively ended his career.
It has been a revolving door of southpaws in the Nationals' bullpen over the past couple of seasons and Garcia may just end up being another name on that laundry list, but I believe he has shown enough in August and September to warrant a roster spot to start 2024.