Royals' most glaring bullpen need was magnified even further after Brewers trade

The Kansas City Royals pulled off a creatively effective trade on Saturday evening with the Milwaukee Brewers, addressing their need for quality outfielders by acquiring Isaac Collins as well bringing in an intriguing potential back-end bullpen arm in Nick Mears, all at the expense of lefty reliever, Angel Zerpa.

While Zerpa's immense highs and cavernous lows brought on an element of inconsistency that certainly made him expendable for a return like this, his loss certainly leaves the Royals with a hole to fill despite his shortcomings.

Arguably their most glaring bullpen need already this offseason was their bolstering their southpaws, and now their work looks that much more cut out for them.

Royals' most glaring bullpen need was magnified even further after sending Angel Zerpa to Brewers

As touched upon already, Zerpa's 4.18 ERA, 1.38 WHIP and .267 BAA in 2025 was certainly nothing to write home about and is replaceable.

However, that's just the thing, he may be replaceable, but that just means the Royals now must replace him. And this is after the fact that they'd already lost another replaceable lefty arm in Sam Long this winter.

Zerpa wasn't completely without strengths. His 96.5 mph average fastball velocity placed him in the league's 84th percentile and his 63.7% groundball rate placed him in MLB's 99th percentile. And when he was on, he was on, sporting a 1.29 ERA in June and a 2.25 ERA in August.

The Royals are now left with two left-handed options in the 'pen; Daniel Lynch IV and potential converted starter Bailey Falter.

Lynch at one point looked a like a real Swiss Army knife in KC's bullpen and while his 3.06 ERA was impressive, he had his flaws. He went from 2.59 ERA in the first half to a 3.81 ERA on the second half. He's also not a strikeout artist whatsoever with just 5.99 K/9 and walked hitters a below average rate of 3.46 BB/9.

Then there's Falter, who in his four outings as Royal this season - two were starts, two were relief appearances - looked all around ineffective, sporting an 11.25 ERA in 12.0 innings.

For the most part, bullpens are going to be heavier on righties, that's just how it traditionally goes. However, successful bullpens usually have reliable a lefty-on-lefty specialist.

According to MLB.com's Anne Rogers last week, one of the Royals secondary needs was a "a left-on-left arm that could fit in the back of their bullpen".

So, while Zerpa likely wasn't going to be that arm for the Royals, the fact they've fully subtracted a southpaw only magnifies that need further.