
What does the past tell us about the possible future?
There’s no arguing that the D-backs bullpen has been a disaster again this season. After the Toronto series, they had an ERA of 5.42, the 28th-best in the majors. It’s certain to be a focus of Mike Hazen and his team, as we head towards the MLB trade deadline, which this year falls on July 31 at 3 p.m. Arizona time. But getting help here is perhaps the trickiest of areas, because reliever volatility is absolutely and undeniably a thing. So let’s look back at the previous efforts of the team to get bullpen arms around the deadline. How successful were these efforts in bolstering the D-backs’ relief corps?
For the purposes of this, I’m looking at relief arms who arrived in Arizona after June 1. I’m not particularly concerned whether they were traded for, arrived as free agents, or were plucked off the waiver wire. I have also discounted cases where the pitcher in question pitched fewer than ten innings the rest of the way, as not significant.
1999: Dan Plesac and Matt Mantei
The first significant bullpen arrivals came in 1999 as the team pushed for their first NL West title. Plesac had been struggling in Toronto but improved significantly here, posting a 3.32 ERA. However, the big splash was getting closer Matt Mantei from Miami. He was just as good here, notching 22 saves with a 2.79 ERA, and striking out 49 over only 29 innings of work. Though he lost the final game in the NLDS, allowing a 10th-inning homer to Todd Pratt in Game 4. Mantei signed a one-year deal that winter, but then became the first closer bust in team history. For his four-year $22 million contract signed in January 2001, made it onto our feature of worst contracts in team history – the only reliever to do so.
2002 + 2004: Mike Fetters
The reliever so good, we acquired him twice! Well… uh… Coming off the World Series, and on their way to repeating as division champions, Arizona traded with the Pirates to get Fetters, sending Duane Sanchez to Pittsburgh. Fetters wasn’t great, with a 5.11 ERA for the D-backs, though his FIP was actually lower here. We did however, get the classic moment of a Mark Grace impersonation. Allowed to walk at season’s end, he came back in June 2004, but sucked. Not that it was obvious, in a 111-loss campaign. He returned for a third time on the staff, ending up as the Diamondbacks’ bullpen coach for a number of years, until the team cleaned house in October.
2005: Tim Worrell + Buddy Groom
Veteran Worrell came from the Phillies for Matt Kata, and was much better here than in Philadelphia, with a 2.27 ERA, compared to 7.41 before the trade. Not that it moved the needle much for Arizona, though 77 wins was a lot better than they had managed the previous year. With a FIP almost two runs higher, Worrell’s performance was largely illusory, and his career ended after twenty more innings the following year for the Giants. The D-backs also got the even older Buddy Groom for the Yankees, and the 40-year-old finished out his major-league career in the Arizona bullpen.
2008: Jon Rauch
D-backs fans of a certain age may be triggered by this one. When Arizona traded Emilio Bonifacio for Rauch, they were tied for first in the NL West, and thought they were getting a solid closer. He had a 2.98 ERA and 17 saves with Washington, after all. Initially, it seemed the case, Rauch putting up a 1.98 ERA across his first ten outings. But he then melted spectacularly, going 0-6 with a 9.64 ERA thereafter. Those six losses was a key factor in the Diamondbacks’ collapse, as they ended the year two games back in the division. This was very much a poster child about the need for caution with regard to expectations with regard to mid-season bullpen acquisitions.
2010: Sam Demel and D.J. Carrasco
This pair arrived in trades for two beloved D-backs, in Conor Jackson and Chris Snyder respectively. Probably not fair to expect much from Demel, who made his major-league debut the day after the trade, and had a rough campaign, with a 5.35 ERA. He stuck around Arizona for two more years without doing much. Carrasco, then 33 years old, did better, with a 3.18 ERA, but was allowed to walk at the end of the year. Hard to say either made much difference, as the D-backs finished last in the division, with 97 losses. But better times were, unexpectedly, just around the corner…
2011: Alberto Castillo and Brad Ziegler
When a bullpen plan comes together… Castillo was a June free-agent signing, but performed well as a LOOGY [remember them?] He gave up only three ER over 17 outings, though six of those were of the one-batter variety. But the prize was Ziegler, whose ground-ball heavy approach propelled him to a 1.74 ERA as an immensely valuable set-up man behind closer J.J. Putz. He stranded 17 of 21 inherited runners, as the D-backs won their most recent division title, cruising to the crown with an eight-game margin. Ziegler would go on to become arguably the best reliever in franchise history, with a 2.57 ERA across parts of seven seasons as a Diamondback.
2012: Brad Bergesen, Matt Albers and Matt Lindstrom
Well, can’t say the front-office didn’t make some effort, in a variety of ways. Bergesen and Lindstrom both came from Baltimore, the former off the waiver wire, the latter in a post-deadline trade of Joe Saunders. Going by my reaction at the time, this was a case where the team wanted to stand pat, the team getting reliever Alberts for another reliever, Craig Breslow. Worth noting the team had exactly the same record through 74 games as this year, an even .500, and a month later, sat at 51-51. Though of course, in those days, there were only two wild-card teams per league. All three here pitched well enough, combining for 61.1 innings at an ERA of 3.06. The D-backs did not make the post-season.
2017: David Hernandez.
There are times when you don’t need to do much. The Arizona bullpen in 2017 was – maybe for the last time? – a genuine strength. In the first half, they went 17-8 with a 3.45 ERA, which was top five in the majors. Archie Bradley and Andrew Chafin had an ERA below two, with support from T.J. McFarland (2.39). So it’s no surprise the team largely stood pat in this area at the deadline. But there was a reunion with Hernandez, who returned from the Angels in exchange for Luis Madero. The results were mediocre, with a 4.82 ERA, but he still made the post-season roster, missing the classic wild-card game against Colorado, before pitching twice against Los Angeles in the NLDS.
2018: Matt Andriese, Jake Diekman and Brad Ziegler
Maybe bringing Ziegler back would re-capture the magic of 2011? Narrator voice: it did not. Though it wasn’t particularly Brad’s fault. He had a respectable 3.74 ERA over the final 29 games of his major-league career. Andriese and LOOGY Diekman however, were much more the problem than the solution. Arizona had reached the deadline just about clinging on to first, after roaring out of the gate. But that pair were 0-4 with an 8.37 ERA after coming to the D-backs, in a spectacular fall from grace. Arizona went 8-19 in September, and missed out. The only plus is that neither cost us much in prospect capital.
2021: Jake Faria, Brett de Geus, Sean Poppen and J.B. Wendelken
The year of Mike Hazen’s dumpster diving for relievers. Though given the team’s race to 110 losses, I can’t blame him for not bothering to make much effort. Faria was a free agent signing, and the other three all came off the waiver wire, at various points between June 25 and August 11. It was clear a case of, throwing pitchers at the bullpen wall and seeing what stuck. All four of them ended making at least twenty appearances for the D-backs, with Poppen and Wendelken doing best – or, perhaps more accurately, least worst, since none of them had an ERA+ in three digits. They both ended up sticking around into 2022, though neither survived long into the rebuild.
2022: Reyes Moronta
I only remember one thing about Moronta, who was picked up off waivers from the Dodgers. The pitcher, nicknamed El Tibu (the shark), was an impressively large human. Baseball Reference lists him at 265 lbs, which is startling considering he was just 5’10” tall. Only three major leaguers under six feet tall have been heavier than that: Bartolo Colon, Prince Fielder and Pablo Sandoval. Moronta appeared seventeen times for the D-backs with a 4.50 ERA. Sadly, while looking him up, I discovered that he was killed in a traffic accident in his native Dominican Republic last July.
2023: Ryan Thompson and Paul Sewald
This is often touted as the gold-standard for relief upgrades, the team signing free agent Ryan Thompson and trading for closer Paul Sewald. However, often forgotten is that the D-backs bullpen was still terrible in August, the month after Sewald arrived – their collective ERA was 5.61, and Sewald’s was 4.66. It only came together in September (6-1 with a 2.31 ERA) and then into the post-season – well, until the World Series at least. But were these good moves, or simply catching reliever volatility in a bottle for two months? Sewald’s overall ERA here including the playoffs was 4.28, and Thompson this year has become one of the chief bullpen scapegoats.
2024: Thiago Vieira, A.J. Puk and Dylan Floro
Finally, we have last year’s attempt, which fell just short of pushing the team across the finish line. Puk, obviously, was grand – 30 appearances and a 1.32 ERA. Let’s not forget Vieira though, who chipped in with a 2.87 ERA across 15.2 innings. But let’s try and forget Floro’s ugly 9.75 ERA across 16.1 innings. But Puk and Vieira are now both rehabbing from elbow surgery (the latter being released by the D-backs a month later), while Floro is in the Athletics minor-league system. It’s more proof that few things in life are guaranteed, especially when it comes to relief pitching. Which is why I’m always dubious about paying a high price for any bullpen arm, even a rental.
Conclusions
The table lists those pitchers, along with their ERA before and after coming to Arizona. All told, they were a little less than half a run worse here. This isn’t too surprising. In terms of trade targets, you’re more likely to be looking at arms that are better than average. But such pitchers will tend to regress towards the mean. There are exceptions to this general rule, of course, going back all the way to Plesac in 1999. There are “bad” pitchers who turned good (Worrell), and those who went the other way (Floro). This may be inevitable given the tiny sample-size of post-deadline work. Only a couple – Worrell and Faria – threw as many as thirty innings for Arizona. Over that range, anyone can achieve almost any result.
So, yes. The Diamondbacks should look to strengthen their bullpen over the coming month. That’s the simple, and highly obvious part. But how they should do it is, a lot harder to say, because there are few guarantees, or even likely things, with regard to relief pitchers. Hazen has a really poor track record with regard to building a bullpen – it might be his most glaring weakness as a GM. This year seemed like it might, finally, be different, but injuries and ineffectiveness have left the team right back where they were, or even worse. The good news? Just two months of decent bullpen could still get Arizona into the post-season. The bad news? I’ve really no idea how we would get there from here.