Diamondbacks Relievers — A Detailed Look Going into Spring Training 2022

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Diamondbacks Relievers in Detail Going into 2022

The 2021 season was a disaster for the Arizona Diamondbacks. Diamondbacks relievers had it especially rough, with the corps finishing last in the National League in almost every meaningful category. However, there were bright spots, even before considering the Mark Melancon signing. Using the reliever evaluation methods discussed in this piece, we’ll look at those few bright spots and what they mean for the Diamondbacks going into 2022.

The top five NL closers for 2021 were Melancon, Josh Hader of the Milwaukee Brewers, Kenley Jansen of the Los Angeles Dodgers, Will Smith of the Atlanta Braves, and Jake McGee of the San Francisco Giants. In this analysis, we will refer to these five collectively as the “NL Elites.” Their performances are included for the sake of comparison. Without further ado, let’s dive in.

(Editor’s Note: As of press time, the reported signing of Ian Kennedy had not been confirmed by the team. Therefore, he is excluded from this analysis.)

WHIP: Getting Outs

Since a pitcher’s primary job is getting people out, let’s look first at WHIP (Walks & Hits per Inning Pitched). The league average for WHIP in 2021 was 1.327. Diamondbacks relievers had a WHIP in 2021 that was higher — 1.517. Of the 2022 players, including those who are in the minors, the top performers were Noe Ramirez (0.888), Tyler Gilbert (1.091), Caleb Smith (1.147), Humberto Castellanos (1.200), Mark Melancon (1.222), and J.B. Wendelken (1.286). For reference, Josh Hader had a WHIP of 0.835, Kenley Jansen had 1.043, Will Smith had 1.132, and Jake McGee had 0.905.

Players with significant use in 2021 who had WHIPs near the league average were, for reference, Tyler Clippard and Joakim Soria. Clippard had a WHIP of 1.303, and Soria had a WHIP of 1.330. Neither is with the team anymore. Those with high WHIPs include Matt Peacock, Taylor Clarke, Joe Mantiply, and Alex Young. Peacock had a WHIP of 1.490 in relief, while Clarke had 1.553, Mantiply had 1.563, and Young had 1.587. Only Peacock and Mantiply are still within the organization.


WHIP says how many baserunners a pitcher allows but doesn’t distinguish between different types of hits. Two statistics that do so are XBH% and X/H%. The former stands for extra-base hit percentage, which measures how often a plate appearance ends in an extra-base hit. In 2021, the Diamondbacks relievers had an XBH% of 9.5%, by far the highest in the NL and well higher than the league relief average of 7.6%. Even worse, the next highest team relief XBH% was 8.2%, giving the Diamondbacks relief corps the highest rate by a significant margin.

On an individual basis, there were several pitchers whose rates were well below the league average. One excelled in this category — Noe Ramirez, whose XBH% as a Diamondback was 3.8%. Other top performers were Mark Melancon (4.9%), Caleb Smith (5.9%), Sean Poppen (6.1%), Humberto Castellanos (6.1%), and Luis Frias (6.3%). By comparison, of the NL Elites, only Hader (3.1%) had a lower XBH% than Ramirez. Jansen had a lower one than Melancon, with 4.0%. However, the remaining two of the NL Elites were higher than Frias, as McGee was 6.7% and Smith was 9.5%.

Tyler Gilbert and Matt Peacock were slightly below the league average, with 7.1% and 7.4%, respectively. J.B. Wendelken was slightly higher than the league average, with 7.8%. Diamondbacks relievers with significant use who had concerning XBH% were, of those still in the system, Stefan Crichton (8.5%), Joe Mantiply (9.6%), Brett de Geus (9.9%), and Kevin Ginkel (12.4%). Recall that Crichton and Ginkel started the season in the majors but were sent down for good in June. (Crichton was a temporary emergency COVID call-up from July 31 to August 1.)


The other percentage we’re examining is X/H%, which shows what percentage of the hits go for extra bases. This supplements WHIP by showing how often baserunners immediately reach scoring position. The league average for NL relievers in 2021 was 36.8%. Diamondbacks relievers collectively had a X/H% of 39%, second-highest in the NL behind the Reds (40%), with the Rockies and Milwaukee Brewers being tied for third (38%).

Mark Melancon had the lowest X/H% on the relief corps, with 24.1%. That was also the lowest among the NL Elites, with Hader having 28.0%, Jansen having 30.6%, McGee having 36.4%, and Smith having 55.1%. Of the 2022 Diamondbacks relievers, Sean Poppen had the second-lowest X/H% in 2021, with 25.0%. Others who performed well in this department were Peacock (27.4%), and Ramirez (27.8%).

Diamondbacks relievers who performed slightly below the NL average were Crichton (30.3%), Aguilar (33.3%), Caleb Smith (33.3%), and de Geus (35.5%). Castellanos and Mantiply — 37.5% and 37.8%, respectively — were slightly higher. Wendelken (40.0%) was not only higher than the league average but also higher than the team average. Of those still in the system, Ginkel had the highest of anyone who saw significant time — 53.3%.

Run Prevention

The reason that a pitcher’s main job is to get opponents out should seem obvious — no baserunners means no runs. As covered in this piece here, ERA and ERA– were designed more for starters than relievers. We’ll include them as a baseline but add scoreless outing percentage to give a better snapshot of how effective these relievers were at preventing runs.

ERA, ERA–, Scoreless Outing Percentage

We’ll start with ERA and ERA-minus as points of reference, with ERA-minus appearing in parentheses. For the sake of comparison, here are the NL Elites. Smith had an ERA of 3.44 (76), and McGee had 2.72 (66). Jansen had 2.22 (53), while Hader had 1.23 (29).

Melancon was 2.23 (57), which is better than all returning Diamondbacks relievers. Wendelken and Poppen were 4.34 (104) and 4.30 (103), respectively. Mantiply was much better than the league average, with 3.40 (82). Ramirez was even better than Mantiply, being equal to or better than two of the NL Elite with 2.76 (66).

However, Mantiply and Ramirez were in the 30s when it came to innings pitched. Wendelken and Poppen were in the teens. Those who know how ERA is calculated know that a small amount of innings pitched means that a bad inning can make an ERA deceptively high. Mantiply and Ramirez pitched enough innings for the good to wipe out the bad. This is where Scoreless Outing Percentage — how often a reliever’s outings that resulted in no runs allowed — paints a more accurate picture.

The NL average for Scoreless Outing Percentage was 69.4%. Mantiply came in at 71.9%. Poppen and Wendelken both finished with 75.0%. Melancon had a rate of 76.6%, while Ramirez had one of 80.6%. For comparison, the rest of the NL Elites had the following percentages: 71.8% for Will Smith, 82.3% for Jake McGee, 82.6% for Kenley Jansen, and 90.0% for Josh Hader. By using only ERA, Poppen and Wendelken appear to be less effective than they truly were, while Mantiply appears to be more effective than he really was.

Pitching with Command: K%, BB%, K–BB%

Pitchers also must have command of the strike zone to be effective. A trio of stats that, in congress, measures command of the zone is strikeout percentage (K%), walk percentage (BB%), and the difference between the two (K–BB%). Strikeout percentage measures how often plate appearances end in a strikeout and walk percentage does the same for walks.


The top Diamondbacks relievers in strikeout percentage were Tyler Gilbert (in his relief appearances, 35.7%), Sean Poppen (25.6%), Caleb Smith (in his relief appearances, 25.0%), Kevin Ginkel (24.0%), and Mark Melancon (22.3%). In 2021, the NL average for relievers was 23.8%. The Diamondbacks relief corps as a whole had a K% of 19.1%. The NL Elites saw Hader with 45.5%, Jansen with 30.9%, Smith with 30.7%, and McGee with 24.3%.


In walk percentage, the Diamondbacks relievers were slightly better than league average with 9.4% vs. a league average of 10.1%. Two pitchers with the best BB% are on the minor league roster, Riley Smith (4.8%) and the struggling-to-stay-healthy Chris Devenski (5.7%). Another is Matt Peacock, who is on the 40-man roster but ended 2021 in Reno. Ramirez (8.3%) and Poppen (8.5%) round out the top five. The NL Elites finished in the following order: McGee (4.2%), Melancon (9.4%), Will Smith (9.9%), Hader (10.7%), and Jansen (12.9%).


The Diamondbacks relievers had a smaller K–BB% than the league average. Their K–BB% was 9.7%, 4.1 percentage points lower than the NL average for relievers (13.8%). The top performer was Gilbert (as a reliever), who had a whopping K–BB% of 21.4%. Behind him were Poppen (17.1%), Caleb Smith (as a reliever, 15.3%), Ramirez (13.6%), and Ginkel (13.2%). The NL Elites finished in the following order: Hader (34.8%), Will Smith (20.8%), McGee (20.1%), Jansen (18.0%), and Melancon (12.8%).

Goose Eggs

Late-inning relief was a disaster for the Diamondbacks in 2021. The best measurement of clutch late-inning relief is the goose egg, developed by Nate Silver of fivethirtyeight.com in 2017. Of the 2022 Diamondbacks relievers, Melancon had the most goose eggs by far, with 35. Ramirez was next, with 11, followed by Wendelken (8) and Mantiply (6). Among the rest of the NL Elite, Jansen was the leader, with 38, followed by Smith and McGee (34). Hader had 33.

Broken eggs are the negative counterpart to the goose egg. Melancon had six of these. Ramirez had three, while Wendelken had one and Mantiply had six. In the NL Elites, Jansen had seven, Smith had eleven, McGee had seven, and Hader had three.


Obviously, more goose egg situations give more chances for broken eggs. For that reason, goose-egg-to-broken-egg ratio (GE/BE) is important. The ratio matters more than the raw goose egg and broken egg totals. Historically — dating back to 1921 — the average ratio has been roughly three to one. In 2021, the NL and AL both had ratios as a league of 2.9 to one. The Giants had the best ratio in the NL, with 4.9 to one; the Diamondbacks had the worst, with 1.5 to one. If it felt like the Diamondbacks had a 50–50 chance to give up an earned run late in a game while holding a narrow lead, well…it’s because they just about did.

However, there were Diamondbacks relievers who not only had a higher ratio than the league average but were well higher. (For brevity, all ratios are ___ to one, so we’ll leave off “to one.”) Wendelken had the best ratio (8.0), followed by Melancon (5.8) and Ramirez (3.7). Mantiply had a straight one-to-one ratio. The NL Elites saw Hader with the best ratio — a mind-boggling 11.0. Jansen had 5.4, while McGee had 4.9 and Will Smith had 3.1.

WPA, Shutdowns, Meltdowns

Goose Eggs do well for clutch late innings. However, they only cover specific scenarios. They’re akin to a pass/fail grade. Sometimes a reliever’s performance is lights-out dominant. Other times he gets the job done but gives his coaches and fans a heart attack in the process. On the negative side, sometimes a reliever pitches fairly well but doesn’t quite get over the hump. And, of course, there are outings that are utter disasters.

How do we quantify these? Using Win Probability (Win Expectancy), we can look at a reliever’s Win Probability Added (WPA) on a game-by-game basis and categorize these outings. If, in his outing, he increases his team’s Win Probability by .060 (6%) or more, it’s a shutdown. The opposite of that — decreasing his team’s Win Probability by .060 or more — is a meltdown. These two categories, tracked on Fangraphs, work together to give us an in-depth look at how effective a reliever has been in a season.


The NL Elites saw strong WPA numbers, as should be expected. Hader led the five with 4.837, which means that, when combining all of his outings, he increased his team’s chances of winning by 483.7 percentage points. Melancon had 3.013, followed by Jansen with 2.993, McGee with 2.845, and Will Smith with 2.029.

Of the 30 Diamondbacks pitchers who made a relief appearance in 2021, only seven had a positive WPA value for the season. That means that only seven left games in better condition than they found them. Only five of them are still in the system. The top returning Diamondbacks reliever in WPA was Ramirez, with 0.336. Next was Wendelken, with 0.300, followed by Gilbert (as a reliever), with 0.102. Miguel Aguilar, who is currently in the minors, had 0.089, and Caleb Smith had 0.051 in his relief appearances.

Shutdowns and Meltdowns

The NL Elites all had 33 shutdowns or more in 2021. Hader had 37 shutdowns in his 54 medium- or high-leverage situations, a percentage of 68.5%. Jansen had 38 out of 56 (67.9%), while Will Smith had 39 out of 57 (68.4%) and McGee had 33 out of 54 (61.1%, .1 forever). Incoming Diamondback Mark Melancon had 36 out of 54 — 66.6% (.6 forever). Of the returning Diamondbacks, Ramirez had the most shutdowns, with 12. Since he had 21 medium- or high-leverage appearances, this was 57.1%. Wendelken had eight out of fifteen, 53.3% (.3 forever).

Among returning Diamondbacks relievers, Joe Mantiply had the most meltdowns, with 11. This was the same amount of meltdowns as Will Smith of the Atlanta Braves, but Mantiply only had 33 medium- or high-leverage appearances compared to 57 for Smith. Of the other NL Elites, Hader had three meltdowns out of 51, Jansen had eight out of 56, McGee had 10 out of 54, and Melancon had seven out of 54. Back to the Diamondbacks, Ramirez had five meltdowns out of his 21 medium- or high-leverage appearances. Wendelken had three out of fifteen.

Relief Outlook

There is certainly much work to be done. One key is Mantiply, a lefty. He needs to become more consistent. As seen by the statistics, Mantiply has the capability to shut teams down, but his team-leading 11 meltdowns made 2021 a hit-or-miss season for him.

On the positive side, signing Melancon was a huge boost. He gives the Diamondbacks a veteran relief presence that they have lacked in recent seasons — sustained and recent success without being washed up. Wendelken and Ramirez should team up with him to make a formidable trio of back-end relief, something the team sorely needs. If the Diamondbacks enter the seventh with a lead, they will depend on the trio to slam the door on their opponents. Unless the Diamondbacks make some other moves, look for Wendelken to pitch the seventh, Ramirez to pitch the eighth, and Melancon to pitch the ninth. Results should be much better than 2021.

After all, it would be close to impossible for them to be any worse.

Main Photo:

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Players mentioned:

Mark Melancon, Josh Hader, Kenley Jansen, Will Smith, Jake McGee, Ian Kennedy, Noe Ramirez, Tyler Gilbert, Caleb Smith, Humberto Castellanos, J.B. Wendelken, Tyler Clippard, Joakim Soria, Matt Peacock, Taylor Clarke, Joe Mantiply, Alex Young, Sean Poppen, Luis Frias, Stefan Crichton, Brett de Geus, Kevin Ginkel, Riley Smith, Chris Devenski, Miguel Aguilar