How Much Has the Three-Batter-Minimum Rule Impacted Lefty Relievers? And How Is it Impacting Free Agency?

We all know that you want at least SOME lefty relievers in your bullpen; er, well, at least you want some guys who are really good at getting lefty bats out, and those tend to be fellow lefties more often than not. But we also know that, since the advent of the three-batter-minimum rule in 2020, the ability to match-up lefties on lefties is somewhat neutered.

In the days of the LOOGY (lefty one-out guy), especially when your bullpen was nine+ relievers, it was worth it to have a lefty who just owned other lefties, even if he was facing only one batter per game, and only a couple times a week. Nowadays, though, since relievers have to face at least three batters (or reach the end of the inning), it’s way too easy for opposing managers to construct lineups – and make in-game switches – that would greatly reduce the value of having a LOOGY.

Here’s the question, though: how much has actually changed in this area? How much value have lefty relievers actually lost? And is there a relationship to the current glut of quality lefties still on the free agent market?

Jake Mailhot took on those questions at FanGraphs, logging the data on the downward trend of lefty reliever effectiveness the last few years, relative to righty reliever performance. That’s not a surprise, when fewer platoon-advantaged match-up opportunities are available. Match-up lefties are just not as valuable as they once were (and lefty relievers overall saw some of their effectiveness decline). Not a shocking conclusion, but it’s interesting to review the data all the same.

What’s really odd in relation to the free agent market is that, among the lefty relievers who have signed, many are guys with huge platoon splits – they are much better against lefties than righties … but you would have expected those guys to be signing last. Conversely, the one reverse-split lefty who signed early? It’s Matt Strahm, the very guy whose two-year, $15 million deal with the Phillies is reportedly holding up the market for the other lefties.

So, then, you wonder if the Phillies got really aggressive on Strahm because of his reverse split – which is unquestionably more valuable in the current era – and then other free agents adjusted their prices accordingly … but teams balked? And then teams pounced on the bigger platoon split guys because they perhaps saw an inefficiency and a market overcorrection? Like, lefties with big splits can still be useful if they can at least hang in there against righties.

As things stand now, guys like Andrew Chafin, Matt Moore, and Zack Britton are all split-neutral lefties, so you can see why they would be the most attractive overall, and also the priciest of the remaining lefty relievers. Brad Hand and Will Smith, by contrast, have more traditional splits, which makes them slightly less valuable in the post-2020 era. Maybe that means they’ll be the first to sign on undermarket deals?

You have to keep in mind, that because of the three-batter rule, split-neutral RIGHTIES are now even MORE attractive than they once were, which means these lefties were also competing with those guys in free agency. Circling back to my opening paragraph, getting lefties out consistently is not the exclusive province of lefty relievers. You don’t *HAVE TO* have multiple lefties in your bullpen (the Cubs could go after righty Michael Fulmer from here, for example). It’s just that, on the balance, if you could have a couple lefties out of your eight relievers, that’s likely to give you the best match-up opportunities on a typical day.

Long story short? In the current era, split-neutrality is probably as valuable as ever among relievers, and that is probably yet another reason for guys like Chafin, Moore, and Britton to stick to their guns on higher price tag demands. Obviously we know that eventually the market is the market, and you have to take what you can get, but it sure seems like they are among the more valuable lefty relievers out there because they don’t have to be leaned on for match-ups.

Oh, and since you were probably wondering: the lone lefty currently locked into the Cubs’ bullpen, Brandon Hughes, did not have an enormous split last year. Yes, righties hit him better (.309 wOBA) than lefties (.277), but that’s just a guy who was effective against both types.