Presenting the Yankees’ Reliever Confidence Index

Caleb Ferguson, one of the more established relievers in the Yankee bullpen, threw over 200 innings with the Dodgers over the course of five seasons before being traded to the Yankees this offseason. He’s mainly looked the part so far, allowing only one run in five appearances and collecting two holds, including a save in extra innings against Arizona.

There are some red signs, however. The lefty’s chase and whiff percentages are significantly lower, raising questions about the sharpness of his stuff. Ferguson’s four-seam fastball velocity has also dropped a few ticks, and it is being hit; on nine batted balls, he has surrendered three hits, including a home run.

Confidence Level: Medium

While the numbers are encouraging, there are some underlying clues that Ferguson may have had some good luck this season, as evidenced by his anticipated ERA of 6.69. It’s still early, and he may easily settle in closer to his career numbers as the season goes. In the meantime, pay attention to how comfortable hitters appear in the box against him.

Victor González

Recent results: 4.2 IP, 1.93 ERA, 1 SO, 216 ERA+

Underlying metrics: 21.6% Chase Rate (17th percentile), 22.6% Whiff Rate (36th percentile), 31.3% Hard-Hit Rate (75th percentile), 5% Strikeout Rate (1st percentile), 15% Walk Rate (14th percentile)

Victor González, another proven lefty reliever acquired from the Dodgers this offseason, is off to a similarly good start as Ferguson. The 28-year-old allowed two runs (one earned) in an appearance against Arizona on April 2nd, but has since had only scoreless appearances, including one in which he won a save in the same Diamondbacks series.

However, González is missing fewer bats and allowing harder contact than he has in years past. His 1:3 strikeout-to-walk ratio is a concern as well, though it’s early to read too much into that metric.

Confidence Level: Medium-Low

González has been a useful but unspectacular middle reliever throughout his career. While his results thus far have been better than in previous seasons, his underlying metrics indicate he may be in for a difficult period. González’s greatest job at this juncture is in low-leverage situations or against lefties (he has held left-handed opponents to an OPS 67 points lower than righties in his career), unless he can exhibit more consistent success.

Nick Burdi

Recent results: 3.2 IP, 0.00 ERA, 4 SO

Underlying metrics: 30.4% Chase Rate, 27.5% Whiff Rate, 25% Hard Hit Rate, 25% Strikeout Rate, 18.8% Walk Rate

Nick Burdi had a long and winding route to the Yankee bullpen. Burdi was selected in the second round by the Twins out of Louisville in the 2014 MLB Draft. He spent portions of three seasons with the Pirates until his second Tommy John surgery terminated his time in Pittsburgh. An ill-timed appendectomy limited him to just three games with the Cubs last season, but he wowed the Yankees with a good spring performance (2 runs and 13 strikeouts in 7.1 innings).

The 31-year-old has not been charged with a run this season, despite appearing in three close games in the eighth or ninth innings. And, despite the tiny sample size, Burdi has induced weak contact at an outstanding rate, with his four-seamer averaging an eye-catching 97.6 mph.

Confidence Level: Medium-Low

No criticism on Burdi here; it’s just difficult to have too much trust in a man who entered the season with 15.1 mediocre MLB innings and 3.2 good ones to begin the season, no matter how brilliant he’s looked. Given how he’s been employed so far, Burdi will most certainly continue to receive opportunities in higher-leverage positions as long as his results remain excellent. If he takes advantage of those opportunities, he may quickly climb both the confidence index and Boone’s bullpen hierarchy.

The Long Reliever

Luke Weaver

Recent results: 7.2 IP, 4.70 ERA, 2 SO, 86 ERA+

Underlying metrics: 31.8% Chase Rate (75th percentile), 15% Whiff Rate (4th percentile), 42.9% Hard Hit Rate (34th percentile), 5.7% Strikeout Rate (2nd percentile), 8.6% Walk Rate (55th percentile)

Luke Weaver has mostly been a starter during his nine-year career, making 106 starts, three of which were with the Yankees at the end of last season.

The former first-round pick has moved to a multi-inning relief job, ditching his breaking pitches in favor of a four-seam/cutter/changeup delivery combination. The results have been mixed: two scoreless appearances, but two in which Weaver allowed runs, including a three-run disaster that allowed Toronto to recover from a 9-2 loss.

Looking behind the hood, the right-hander’s chase rate has improved significantly this season, but the rest of his advanced metrics are at best ordinary. His low strikeout and whiff percentages, in particular, indicate that his improved repertoire is not allowing him to miss many bats.

Confidence Level: Low

For better and for worse, Weaver is a fairly known quantity at this point. It would be alarming to see him assume a more prominent back-end bullpen role, but as long as he’s deployed in lower-leverage spots, he can still be a serviceable option.

The Mop-Up Men

Dennis Santana

Recent results: 4.1 IP, 6.23 ERA, 3 SO, 68 ERA+

Underlying metrics: 32.5% Chase Rate (78th percentile), 15.6% Whiff Rate (4th percentile), 38.5% Hard Hit Rate (47th percentile), 16.7% Strikeout Rate (23rd percentile), 11.1% Walk Rate (32nd percentile)

Santana, who signed a minor-league contract this summer, did not make the Opening Day roster after a strong spring training. He was brought up to replace Loáisiga on April 5th and has had a disappointing start to the season. The right-hander was charged with three runs in 4.1 innings, two of which came after he exited the game and the third after a sloppy inning highlighted by an Anthony Volpe mistake.

Santana, who turned 28 yesterday, has gotten a respectable percentage of hitters to chase, but his advanced numbers are below average. Particularly concerning is his whiff rate, which has been a strength throughout his career but is now in the fourth percentile. If you don’t miss bats and allow reasonably heavy contact on a regular basis, you won’t have many clean innings.

Confidence Index: Nonexistent

Santana’s lifetime 5.20 ERA in 154 innings suggests that his fortunes are unlikely to alter anytime soon. Barring a big reversal, he should be employed solely in low-leverage situations to eat innings, rather than as part of the Yankees’ successful bullpen recipe.

Josh Maciejewski

Recent results: 1 IP, 0.00 ERA, 0 SO

Josh Maciejewski, a homegrown player who was picked in the tenth round out of UNC Charlotte in 2018, made his MLB debut on April 8. He entered in the ninth inning, inducing three grounders to Jon Berti at third to retire the side on four pitches and seal a 7-0 Yankee victory.

Last year, the left-hander posted a 2.96 ERA with 46 strikeouts in 45.2 innings across three different minor-league levels.

Confidence Index: N/A

It’s simply too early to draw any conclusions about Maciejewski. His only appearance to date in a blowout implies he is a pure innings eater who will need to outperform expectations to secure a more important role. Expect the 28-year-old to be one of a handful of pitchers (along with Santana, Jake Cousins, and Tanner Tully) who will move between Triple-A and the bottom of the Yankee bullpen’s pecking order dependent on their usage to help keep the Yankees’ primary relievers fresh.