Last 30 Day Non-Closing Reliever SwStk% Leaders — Through Jul 24, 2023

If you only play in a 12-team mixed or shallower league, chances are you have rarely, if ever, rostered a non-closing relief pitcher, let alone included him in your active lineup. However, in deep leagues, especially mono formats, non-closing relievers can earn meaningful fantasy value, even without recording a single save. As starting pitcher innings have declined (only eight amassed at least 200 innings last year, versus a whopping 31 back in 2012, for example!), the gap in wins and strikeouts between starters and relievers have shrunk, increasing the value of relievers vs starters in deeper fantasy leagues. So these relievers are now more valuable than they had been, which means it’s worth researching them regularly, as pitchers are promoted from the minors all the time.

With that in mind, let’s review the last 30 day non-closing reliever SwStk% leaders. Some of these pitchers may also be next in line for saves, which is especially timely given the upcoming trade deadline.

Boy, the Rays truly are a pitching factory. Remember Robert Stephenson? He was a former top starting pitcher prospect for the Reds, many years ago. He’s now 30 years old, is obviously no longer a prospect, and sports a career 4.84 ERA. He has been a full-time reliever since 2019, his ERAs have been all over the place, and he’s now with his fourth organization since 2020. The good news is, he also sports a career 14.2% SwStk%, so clearly he has some elite stuff. Sounds like a perfect Rays reclamation project!

It’s only been 16.1 innings in a Rays uniform, but he’s posted a crazy 28.1% SwStk% and 38.1% strikeout rate, while only walking 7.9% of opposing batters (versus a 10.5% career mark). He has thrown his four-seam fastball less frequently than he ever has, has introduced a cutter that he has now thrown 44.6% of the time, upped his changeup usage, and reduced his slider usage. Though, it’s possible there’s no actual cutter and it’s just his slider that he’s throwing harder now. Whether you call it a cutter or a reimagined slider, it has generated an epic 39.8% SwStk% so far. Holy guacamole!

Oh, and he still averages 97 MPH with his fastball, so his repertoire is seemingly the eliteiest of the elite. The Rays haven’t typically settled on a closer in the past, but they have done so this year, so there’s less of a chance for him to record a save. Still, it’s possible Stephenson tallies a save or two over the rest of the season. Even if he doesn’t, his strikeout potential makes him a nice target in deep leagues.

Wherever the good Aroldis Chapman went last year, we will never know. But he has returned this year in typical form — striking out a ton of batters, and also walking too many. One look at his velocity trend and it’s pretty clear what happened — his fastball velocity was down last year to a career low and has rebounded this year nearly two miles per hour to his highest since 2017. His slider is similarly up to its highest since 2016. So as long as he could maintain this velocity rebound, he should keep striking out batters like he has during his vintage years.

When Chapman was traded to the Rangers, there was a possibility he would take over the closer role from Will Smith. He did earn one save fairly quickly, but it’s been Smith during every other save attempt. That he allowed three runs in his last outing should further solidify Smith in the role, but it’s still possible, and perhaps likely, that Chapman picks up another save or two the rest of the way. He should definitely be owned in deeper leagues for his strikeouts.

What I love about producing these lists is inevitably, I encounter pitchers I’ve never heard of. It’s hard to be aware of every middle reliever in baseball, and Kyle Nelson is one of them! As a southpaw on the Diamondbacks, there’s mixed potential for saves here. On the one hand, lefties don’t earn as many save opportunities since they don’t usually have the platoon advantage. However, the Diamondbacks bullpen is quite unsettled and anyone could seemingly pop up to grab a save.

Nelson doesn’t throw hard, averaging just 92.3 MPH on his four-seamer, but he throws his slider a ton, nearly 60% of the time. The pitch has generated an elite 22.7% SwStk% and he actually holds pretty even xFIP splits against batters from both sides of the plate. He’s a nice darkhorse saves speculation in deep leagues right now.

Marlins closer A.J. Puk has been brutal in July, posting a 9.82 ERA, which has possibly opened the door for a new reliever to take on the role. That reliever might be Tanner Scott, who earned 20 saves last year. He has always featured quality stuff, with high SwStk% marks and strong strikeout rates. So a big number in those metrics over any sort of sample size is no surprise. The struggle for Scott has always been his control. This year, he has seemingly improved that, as he has finally gotten his walk rate down into single digits. But walk rates are sometimes fickle over small samples, so it doesn’t mean he won’t suddenly struggle with walks again over the next couple of weeks and blow his closer shot.

That said, given his strikeout potential and the fact his control has improved, he’s obviously worth grabbing if you need saves. You’ll just need to keep your fingers crossed.

Dominic Leone is highly unlikely to earn any saves over the rest of the season. He’s also a veteran who has recorded just seven career saves, so it’s not like he’s some youngster breaking out. But he’s always posted strong SwStk%, though low called strike rates have ensured his strikeout rate was never anything special. Has he been doing anything differently these past 30 days? He has thrown his four-seamer a bit more at the expense of his cutter, but the real change is his velocity. His four-seamer has jumped 1.4 MPH, his cutter 1.1 MPH, and slider 1.5 MPH. All of these velocities would represent career bests. I have no idea if this was triggered by a mechanical change, something else we could point to, or this is sustainable at all. But for as long as he’s throwing this much harder, he’s a good stopgap in deep leagues when you have a starter with a bad matchup you want to bench for the week.

Jovani Moran is another who is not going to tally a save, but he’s also got some serious swing and miss stuff. His strikeouts have never been an issue, but like Scott above, control has been. He has walked double digit batters at every single minor league stop, except two, during his minor league career, going back to 2015. He’s still just 26, so improved control could suddenly come at any time. Given his lack of control and low odds of recording a save, I’d pass on him.

With an 8/08 fastball and 55/60, the scouting grades tell you that Andrés Muñoz possesses elite stuff. Like some of these other names, it’s no surprise to find him among the SwStk% leaders. While it has been just 110 MLB innings, he owns an incredible 19.7% SwStk% over his short career, driving a 36.3% strikeout rate. These are closer type skills, but he has yet to get that opportunity. Walks have been an issue at times, but it hasn’t been bad enough, especially given his high strikeout rates. Also worth noting is he’s upped his GB% above 60% this year. So with few balls in play to begin with and those that do get put into play mostly getting hit on the ground, he figures to rarely allow a home run. If and when he gets his shot as the full-time closer, he should run with it.