Can the Diamondbacks Bullpen be Fixed?

The lack of strikeout ability from relievers continues to cause problems late in games

© Rob Schumacher/The Republic / USA TODAY NETWORK

As the final few innings of last night's game between the Dodgers and the Diamondbacks played out we saw an all too familiar scenario:

Hard throwing opponent relievers coming in late, racking up the strikeouts and keeping D-backs hitters in check during tight games. Meanwhile Arizona relievers come and allow contact, hits, and walks, unable to get the big strikeouts, leading to runs and losses.

While velocity isn't everything, it's more important for relievers. Velocity correlates strongly to strikeouts. Relievers typically come in when there are runners on base, especially in extra innings. Unfortunately this velocity and strikeout deficit for Diamondbacks relievers has been an issue since 2018.

Year	AZ Avg. FB Velo	NL Avg FB Velo	Rank	AZ K%	NL Avg K%	Rank
2018	92.3	93.6	14th	21.7%	23..2%	11th
2019	92.4	93.8	15th	22.8%	24%	13th
2020	94.0	93.4	6th	22.5%	24.2%	12th
2021	92.4	93.9	14th	19.1%	23.8%	14th
2022	92.5	93.9	14th	19.7%	23.4%	15th

The problem has been even more acute in 2022 in high leverage situations in the 9th and extra innings. The team strikeout percentage in those situations is half the NL average, just 12.8% vs. 24.1% average for the league. Not only does that rank last, but the next worst team, the Reds, are 6% points better.  While Mark Melancon has faced roughly half of the batters this year, (67 of 133) and has just a 14.9% K rate in those situations, it's hardly an issue with just one pitcher. Ian Kennedy has just an 11.9% K rate in these high leverage situations, Joe Mantiply is at 18.2%.  And frustratingly, whenever the team has tried some of their harder throwing relievers such a Reyes Moronta, Kevin Ginkel, Caleb Smith, or the since released Sean Poppen, they've combined to strikeout ZERO of the 13 batters they've faced. 

Spanning the 2020-2022 seasons, this systemic failure to build a bullpen capable of striking batters out has directly lead to the worst bullpen in the National League over the last three seasons, both in high leverage and overall. They rank dead last in the following statistical categories over that span:

WPA (win percentage added). -14.91

RA-9 WAR (-7.2) and FIP* Based WAR (-1.2)

Bullpen losses,  88

They also rank 13th in the more traditional reliever ERA with a 4.81 Mark

*Note: FIP is Fielding Independent Pitching, based on just K's, BB's, and HR allowed. RA-9 WAR is based on all runs allowed, including unearned runs.

How Can the Diamondbacks Fix this issue ?

Free Agency

They are unlikely to sign top  dollar free agent relievers due to limited payroll budgets. Heading into 2023 season, the current payroll snapshot shows they would need to increase the budget significantly to have an impact. The combination of guaranteed salaries, expected arbitration salaries, and the remaining roster spots that must be filled with at least league minimum pre arbitration players still adds up to over 90 million dollars, which is more or less where they are now. Just how much the Diamondbacks may increase payroll for the 2023 season is anybody's guess. But it would probably have to be in excess of a $20M increase to have any significant impact on the bullpen and still address other areas of team need.  So if trying to upgrade the pen via the free agent market, the team would be forced to employ the same strategy that has failed repeatedly over the last several seasons. Buying low on pitchers coming off injury or sub par seasons just has not worked at all for Arizona over the last few years. 

Trade Market

The trade market is another area they can explore. But just how willing the team would be to utilize young position player assets to attempt to bring in a high end reliever or two that might be more affordable from a salary standpoint is questionable. Mike Hazen has not been one to trade away highly ranked prospects for relievers. It would go against his past history. The Diamondbacks do have a glut of outfielders in their system however. In addition to young players already playing in the majors such as  Daulton Varsho, Corbin Carroll, Alek Thomas, Jake McCarthy and Stone Garrett, they have Dominic Fletcher and Dominic Canzone waiting in the wings in AAA Reno as well.  Could the team attempt to draw from that pool of talent to shore up the bullpen? Do any of the players they would be willing to part with have enough trade value to bring in a proven high octane reliever? 

Internal Relief Prospects

In a perfect scenario the Diamondbacks would be solving this issue internally, via draft, international signings and player development. Unfortunately the players they have been bringing up have not succeeded. There are some harder throwers that have made appearances in the majors this year, but they all had issues throwing strikes to varying degrees, and in addition to walking batters, tended to get hit hard when falling behind in counts. What's most notable however is even the harder throwers among young relievers that have made appearances for Arizona this year have failed to achieve league average strikeout rates. The lone exception is Luke Weaver, who was traded to Kansas City for third baseman Emmanuel Rivera.

Jack Sommers

Luis Frias throws the hardest, often topping out over 98 MPH, but he's walked 11 Batters in 14.1 IP.  Several pitchers on this list were released and ended up in other organizations. 

26-year-old Mitchell Stumpo is a minor league reliever with good stuff but he's been unable to harness it. In 41 IP this year he has 31 walks and 48 strikeouts. That walk total keeps the team from calling him up. 

21-year-old Justin Martinez is one of the organization's hardest-throwing arms and was recently promoted to AAA. He's likely to be added to the 40-man roster this winter, but only has 16 appearances since returning from Tommy John surgery. His fastball velocity averages 96 with a top speed of 98 in short bursts to go with a slider and changeup.

Converting a starter

The one area the team has some potential extra depth is among minor league starting pitchers. One young pitcher who throws harder than all of them, Drey Jameson, has often been thought of by prospect evaluators as a player destined to be a closer in the big leagues. He throws over 98 MPH and has the makeup to compete. However he's been so good since getting called up to the majors as a starter that the team is unlikely to convert him to a reliever anytime soon. 

Ryne Nelson had a terrific start to his major league career before coming down with a shoulder injury recently. The team is likely to want to continue his development as a starter as well.

Brandon Pfaadt is going to get every chance to start in the majors next year. 

Slade Cecconi is an intriguing possibility. When he first arrived he was throwing in the high 90's, but has had issues maintaining high velocity the last couple of years. With several starters ahead of him on the depth chart and a track record of high velocity in the past, perhaps he could regain that and become a back end option. 

Tommy Henry is another pitcher who could up his power game out of the bullpen, but the team is lacking in left hand starter options at the moment, so they will probably not look to convert him in the near term. But don't be surprised if Henry is working out of the bullpen next year. Not a hard thrower by any means, in short spurts he could be a tough on left hand batters. 

It's probably long past the time to convert Corbin Martin to reliever at this point

Whatever the team decides to do, it will be more critical than ever to fix the bullpen. The other pieces are already in place to field a competitive team. The playoff window is beginning to crack open a little bit for the D-backs perhaps as early as 2023. But a failure to address the bullpen properly very soon will slam that window shut