1 Reds reliever, not named Alexis Diaz, who's been better than expected in 2023

So far in 2023, the Cincinnati Reds bullpen has been quite underrated. They are led by their closer, and potential All-Star Alexis Diaz. Diaz put together a tremendous rookie campaign last season, but has been even better to start this year.

In 2023, Diaz has already recorded eight saves, and if he stays healthy, will almost assuredly surpass the 10 saves he recorded in 2022. Diaz has improved in almost every area, but most notably his fielding independent pitching (FIP). His FIP, through 13.1 innings, is just 0.52. That's unheard of and is the best among all pitchers with at least 10 inning pitched.

Believe it or not, the Reds rank in the top 10 in team bullpen ERA and strikeouts. This kind of production doesn't happen on accident, and it certainly doesn't happen without production from top to bottom.

Lucas Sims has been better than expected in 2023.

One reliever that hasn't gotten enough credit is Lucas Sims. The right-hander has had his struggles from time to time in a Reds uniform, most notably with command (4.2 career BB/9 according to Baseball Reference). But these issues haven't come back to bite him this season.

In fact, Sims is off to the best start in his major league career. Runs are almost impossible to come by with Sims in the game, while strikeouts are as frequent as ever. His success this season isn't by accident either.

This biggest adjustment that he's made has been his pitch usage. For as long as baseball has been around, almost every pitcher would throw his fastball more often than any other pitch. Sims was never an exception to this rule. Until this year.

In fact, Sims has increased his slider usage by nearly 20% since 2020 according to Baseball Savant. This change is absolutely intentional. A quick look into the numbers would tell you exactly why he made this switch and exactly why it is working so well.

Sims has the ability to spin the baseball as well as anybody in the game, ranking in the 98th percentile in fastball and breaking ball spin rate. Opposing batters can never even muster a batting average above .200 on that pitch.

With that kind of effectiveness, Sims and the Cincinnati Reds coaching staff have made that pitch even more dangerous. Sims has kept runs off the board and opposing batters returning to their dugout in shame. Aside from Alexis Diaz, Lucas Sims has been the most effective pitcher out of the Reds bullpen.