Lucas Erceg: Best reliever in baseball

Since coming to the Royals there is a good case to be made that no MLB bullpen arm has been better than Lucas Erceg.

The Royals acquired Lucas Erceg on July 30th of last season. It was the second relief arm that the Royals picked up in July to try and shore up a very weak bullpen that had caused the team a lot of grief throughout the year. Looking at Erceg at that time, it looked like they had picked up a competent reliever who could take on the 7th or maybe even the 8th and had a lot of team control left, which is a nice piece to add to most any team. Instead, he has turned into one of, if not the most dominant bullpen arm in all of major league baseball, and I think we need to give him his flowers.

Ever since the Royals acquired him last July, here are Erceg’s ranks as a bullpen pitcher (min. 30IP). He is 1st in fWAR at 2.1, t-9th in ERA at 1.77, 3rd in FIP at 1.64, 16th in IP at 45.2, 3rd in walk rate at 0.99 per 9 innings, and 1st in win probability added. He has been as good as anyone. There is very little to critique, except for maybe the strikeout rate, but when you are walking slightly less than one batter every 9 innings, it is hard to get too worked up about it.

That is an absurdly good run, but he has possibly been even better than that so far this year. The ERA so far in 2025 is a minuscule 0.44 and the walk rate is sitting at 0.87 per nine. The only thing to keep it from being definitively better is the 6.53K/9, which is making the xERA/FIP/xFIP numbers good but not elite. Depending on a .176 BABIP and 0% HR/FB is always a little hard to do.

What is interesting is that I don’t think any of this has to do with changes in stuff really, It isn’t velocity changes or new pitches or a pitch playing way better from what I can tell. It is purely increased command and maybe what Stuff+ calls Pitching+. That is a better process overall based on count, handedness, and location. That also happens to be the metric that best predicts reliever performance, so he is doing something right and it tends to be predictive of success for relief pitchers.

The Royals did give up some talent to acquire Erceg, but so far Mason Barnett and Will Klein have not had much success in their new homes. The only player that is performing well for the other side of the trade is Jared Dickey who is hitting .304/.417/.375 in high A ball as a 23 year old, so he could end up mattering in a few years, but with limited upside. This is one heck of a trade considering Erceg will not be a free agent until 2030.

I really do not have lots more to say, I just want to make sure people realize just how good Lucas has been for the Royals. It is a joy to have a reliever come in the game and lock it down over and over again, especially when leads are precious like they are currently. Do not be complacent as fans here. Give Erceg all the love, he deserves it.