Changing the format slightly, this post focuses on reliever performance during May by examining some underlying data and comparing it to the results in April. This yields gainers and decliners of interest with eyes on the future.
First, the leaderboards.
Saves Leaders from May
| Reliever | Saves |
| Ryan Helsley | 9 |
| Jhoan Durán | 7 |
| Emmanuel Clase | 7 |
| Carlos Estévez | 7 |
| Trevor Megill | 7 |
| Kyle Finnegan | 7 |
| Jeff Hoffman | 7 |
| Josh Hader | 6 |
| Luke Weaver | 6 |
| Jordan Romano | 6 |
| Andrés Muñoz | 6 |
| Robert Suarez | 6 |
| Emilio Pagán | 6 |
SOLDS Leaders in May
| Name | Saves | Holds | SOLDS |
| Daniel Palencia | 5 | 4 | 9 |
| Ryan Helsley | 9 | 0 | 9 |
| Tommy Kahnle | 2 | 6 | 8 |
| Jordan Romano | 6 | 2 | 8 |
| Camilo Doval | 1 | 6 | 7 |
| Jhoan Duran | 7 | 0 | 7 |
| Emmanuel Clase | 7 | 0 | 7 |
| Carlos Estévez | 7 | 0 | 7 |
| Trevor Megill | 7 | 0 | 7 |
| Griffin Jax | 0 | 7 | 7 |
| Abner Uribe | 1 | 6 | 7 |
| Kyle Finnegan | 7 | 0 | 7 |
| Ryan Walker | 5 | 2 | 7 |
| Devin Williams | 1 | 6 | 7 |
| Jordan Leasure | 1 | 6 | 7 |
| Ryan Zeferjahn | 0 | 7 | 7 |
| Jeff Hoffman | 7 | 0 | 7 |
Strikeout Leaders in May
| Name | Strikeouts |
| Ronny Henriquez | 22 |
| Griffin Jax | 21 |
| Jhoan Duran | 20 |
| Abner Uribe | 20 |
| Jeremiah Estrada | 20 |
| Randy Rodríguez | 20 |
| Cade Smith | 20 |
| Ben Casparius | 19 |
| Yariel Rodríguez | 18 |
| Jordan Romano | 17 |
| Gabe Speier | 17 |
| Bradley Lord | 17 |
| Garrett Whitlock | 17 |
| Graham Ashcraft | 17 |
Now for the underlying data.
K-BB%
The following relievers had the largest increase in K-BB percentage in May versus April.
Gainers
| Risers | Mar/Apr | May | K-BB% Diff |
| Devin Williams | 4.0% | 27.9% | 23.9% |
| Caleb Ferguson | -1.7% | 22.0% | 23.7% |
| Jordan Romano | 7.8% | 28.6% | 20.8% |
| Ronny Henriquez | 11.9% | 31.6% | 19.7% |
| Yariel Rodríguez | 8.0% | 27.3% | 19.3% |
| Brant Hurter | 10.9% | 28.9% | 18.0% |
| Anthony Bender | 0.0% | 17.8% | 17.8% |
| Daniel Palencia | 9.1% | 26.7% | 17.6% |
| Dennis Santana | 8.7% | 26.1% | 17.4% |
| Ryan Helsley | 4.5% | 20.8% | 16.3% |
| Carlos Estévez | 6.3% | 22.5% | 16.2% |
There are some intriguing names above, and those who targeted Daniel Palencia will be encouraged to see his improved rate in this category; it will be a key to continued success. Two relievers of interest appear on this list: Ronny Henriquez (MIA) and Yariel Rodríguez (TOR). Their roles may expand in their respective bullpens as the season progresses if these gains are sustained.
The following relievers had the most significant declines in this category.
Decliners
| Decliners | Mar/Apr | May | K-BB% Diff |
| Mason Miller | 50.0% | 15.9% | -34.1% |
| Yuki Matsui | 30.0% | 0.0% | -30.0% |
| Tim Herrin | 21.7% | -4.4% | -26.1% |
| Jeff Hoffman | 38.9% | 16.0% | -22.9% |
| Jacob Webb | 15.3% | -3.9% | -19.2% |
| Jason Adam | 22.1% | 4.3% | -17.8% |
| Manuel Rodriguez | 25.5% | 7.7% | -17.8% |
| Shelby Miller | 23.4% | 6.3% | -17.1% |
| Hunter Gaddis | 34.8% | 19.1% | -15.7% |
| Mason Montgomery | 23.3% | 7.7% | -15.6% |
| Shawn Armstrong | 17.9% | 2.4% | -15.5% |
| Ryan Walker | 20.4% | 5.0% | -15.4% |
May was a rough month for Mason Miller, though he flashed signs of a rebound near its conclusion. Hoffman and Walker also suffered in their K-BB percentages and must be monitored closely in June.
SwStr%
These relievers experienced the most significant gains in swinging strike percentage in May compared to their April results.
Gainers
| Reliever | Mar/Apr | May | SwStr% Diff |
| Ronny Henriquez | 12.9% | 22.8% | 9.9% |
| Randy Rodríguez | 12.5% | 20.8% | 8.3% |
| Dylan Lee | 12.4% | 19.3% | 6.9% |
| Matt Strahm | 8.7% | 15.3% | 6.6% |
| Mason Fluharty | 9.4% | 15.9% | 6.5% |
| Carlos Hernández | 7.8% | 14.1% | 6.3% |
| Devin Williams | 10.1% | 16.2% | 6.1% |
| Jimmy Herget | 6.6% | 12.6% | 6.0% |
| Emmanuel Clase | 15.7% | 21.5% | 5.8% |
| Jeremiah Estrada | 15.3% | 21.1% | 5.8% |
| Lucas Erceg | 8.9% | 14.0% | 5.1% |
| Josh Hader | 18.0% | 23.0% | 5.0% |
| Carlos Estévez | 5.8% | 10.6% | 4.8% |
| Seranthony Domínguez | 10.9% | 15.4% | 4.5% |
Once again, Henriquez appears on the gainers list, though his role remains in flux. Even though the Giants have already made one switch at closer, fantasy managers should monitor how Randy Rodríguez gets used during leverage situations in June.
These relievers incurred the most significant drops in swinging strike rate in May versus their results in April.
Decliners
| Reliever | Mar/Apr | May | SwStr% Diff |
| Mason Montgomery | 21.1% | 11.8% | -9.3% |
| Brendon Little | 24.9% | 15.7% | -9.2% |
| Aroldis Chapman | 21.6% | 14.4% | -7.2% |
| Will Vest | 15.4% | 8.3% | -7.1% |
| Scott Barlow | 14.5% | 7.9% | -6.6% |
| Hunter Gaddis | 20.5% | 14.1% | -6.4% |
| Jackson Rutledge | 17.1% | 10.9% | -6.2% |
| Justin Sterner | 14.8% | 8.9% | -5.9% |
| Mason Miller | 23.7% | 18.1% | -5.6% |
| Greg Weissert | 12.1% | 6.5% | -5.6% |
| Ian Hamilton | 16.5% | 11.1% | -5.4% |
| Brock Burke | 13.2% | 8.0% | -5.2% |
| Yuki Matsui | 16.4% | 11.2% | -5.2% |
| Andrés Muñoz | 18.4% | 13.4% | -5.0% |
| Shelby Miller | 16.6% | 11.7% | -4.9% |
| Orion Kerkering | 11.5% | 6.7% | -4.8% |
| Chase Shugart | 11.4% | 6.6% | -4.8% |
| Pete Fairbanks | 13.5% | 8.8% | -4.7% |
| Nick Mears | 13.6% | 9.1% | -4.5% |
| Jeff Hoffman | 18.5% | 14.1% | -4.4% |
| Edwin Uceta | 14.6% | 10.2% | -4.4% |
Do not focus solely on the last column; note the total from April versus May when assessing a reliever of interest on this list. Three relievers from Tampa Bay appear, and it’s not known if moving from the comfortable confines of their indoor stadium to the Single-A park they play in factors heavily in these outcomes, but it’s worth noting.
Last but not least, identifying relievers who produced strong underlying data across four key categories during high-leverage events. These four all recorded a K-BB percentage greater than 20, a swinging strike percent over 15, a strike percentage of at least 65 percent, and a contact rate allowed less than 67 percent:
| Reliever | K-BB% | SwStr% | Strike% | Contact% |
| Jeremiah Estrada | 38.6% | 21.1% | 67.2% | 63.1% |
| Randy Rodríguez | 37.8% | 20.8% | 69.6% | 61.5% |
| Gabe Speier | 36.6% | 18.4% | 72.1% | 65.8% |
| Griffin Jax | 34.0% | 16.0% | 67.1% | 66.3% |
| Josh Hader | 33.3% | 23.0% | 65.8% | 53.9% |
| Ronny Henriquez | 31.6% | 22.8% | 65.3% | 56.1% |
| Brock Stewart | 31.6% | 17.9% | 66% | 63.6% |
| Bennett Sousa | 24.5% | 17.7% | 71.4% | 66.7% |
These relievers just missed, qualifying in three of the four categories:
| Reliever | K-BB% | SwStr% | Strike% | Contact% |
| Bryan Baker | 31.9% | 16.2% | 65.9% | 67.4% |
| Devin Williams | 27.9% | 16.2% | 62.6% | 65.9% |
| Jhoan Durán | 24.2% | 15.2% | 66.7% | 70.6% |
| Tanner Scott | 23.9% | 15.8% | 69.4% | 71.6% |
This concludes our review of May. There are some intriguing names worth tracking in June.
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