Jordan Montgomery May Be Done as a Diamondback, But Brandon Pfaadt Is Sticking Around

Jordan Montgomery isn’t likely to pitch for the Diamondbacks again. Brandon Pfaadt could be pitching for them well into the next decade. That’s the upshot of an eventful few days for the Diamondbacks rotation, as Montgomery revealed last week that he would undergo Tommy John surgery and miss the 2025 season, while Pfaadt agreed to a five-year, $45 million extension that includes a couple of additional option years.

For the 32-year-old Montgomery – who was outpitched by Pfaadt and Ryne Nelson in this spring’s battle for the fifth starter job — this is the latest twist in a saga that has largely been an unhappy one ever since he helped the Rangers win the 2023 World Series. He hit the market on a high note after being dealt ahead of the trade deadline for the second straight season; between his time with the Cardinals and Rangers in 2023, he set career bests while posting the majors’ eighth-lowest ERA (3.20) and ranking 12th in WAR (4.3). He capped that with a 2.90 ERA in 31 postseason innings, starting a pair of series-opening combined shutouts against the Rays (ALWCS) and the Astros (ALCS), and chipping in 2 1/3 innings of emergency relief following Max Scherzer’s injury-related exit in Game 7 of the ALCS. Though he was knocked around by the Diamondbacks in Game 2 of the World Series, it didn’t stop Texas from winning its first championship.

Off of that run, Montgomery and agent Scott Boras reportedly set their sights on a contract topping the seven-year, $172 million extension that Aaron Nola signed with the Phillies shortly after the offseason began, but as with Boras’ other high-profile clients that winter, namely Cody Bellinger, Matt Chapman, and Blake Snell, the big deal envisioned for Montgomery never materialized, and he lingered unsigned past the start of spring training. He was pursued by the Red Sox — which would have been an excellent fit given that his wife had begun a dermatology residence at a Boston-area hospital in the fall of 2023 — as well as the Rangers, Yankees (who drafted and developed him), and Mets, among others. In the end he settled for a one-year, $25 million contract with the Diamondbacks on March 29, with a $20 vesting option for 2025 based on 10 starts, rising to $22.5 million with 18 starts and $25 million with 23 starts.

After signing, Montgomery made two starts for Arizona’s Triple-A Reno affiliate, then debuted for the Diamondbacks on April 19. Three of his first four starts were good, but he struggled mightily thereafter, missed three weeks in July due to right knee inflammation, and was temporarily relegated to the bullpen late in the season. He finished with a gruesome 6.23 ERA and 4.48 FIP, with his strikeout rate plummeting to 15.6% (from 21.4% in 2023), and his walk and homer rates both rising. His average sinker velocity fell from 93.3 mph in 2023 to 91.8 last year, prompting the pitch to get pummeled for a .376 average and .582 slugging percentage. According to both of our pitch modeling systems, his stuff and command declined, with his PitchingBot score falling from 52 to 46 (on the 20-80 scouting scale) and his Pitching+ falling from 97 to 87 (on a scale where 100 is average).

Amid that performance collapse, reminders of Montgomery’s unhappy tour through free agency lingered. The pitcher left the Boras Corporation last April to be represented by Joel Wolfe and Nick Chanock of Wasserman, and in August he told the Boston Herald, “[O]bviously Boras kind of butchered it” with regards to his free agency, or at least his pursuit by the Red Sox following a promising introductory Zoom call.

In the spirit of airing grievances publicly, shortly after the end of the regular season, Diamondbacks managing general partner Ken Kendrick told the Burns & Gambo radio show that signing Montgomery had been “a horrible decision.”

“If anyone wants to blame anyone for Jordan Montgomery being a Diamondback, you’re talking to the guy that should be blamed… Because I brought it to [the front office’s] attention. I pushed for it. They agreed to it — it wasn’t in our game plan. You know when he was signed — right at the end of spring training. And looking back, in hindsight, a horrible decision to invest that money in a guy who performed as poorly as he did. It’s our biggest mistake this season from a talent standpoint. And I’m the perpetrator of that.”

Kendrick’s outspokenness recalled his past public criticism of players such as Stephen Drew and Justin Upton, though in this case, he was more careful, pointing the finger at his own role in the decision-marking process rather than directly at the player. The outburst may have been a ploy to drive Montgomery away, but he nonetheless exercised his $22.5 million option, then spent the winter and spring as the subject of trade rumors. Meanwhile, the Diamondbacks landed an ace in free agent Corbin Burnes, rounding out a solid rotation that already featured Zac Gallen, Merrill Kelly, Eduardo Rodriguez, and Pfaadt, with Nelson the top alternative.

Montgomery told the Burns & Gambo show he didn’t have “hurt feeling” about Kendrick’s comments, saying, “I know my season wasn’t great, and I expect a lot of myself.” He expressed the belief that being overweight factored into his underperformance, adding that he had since lost 20 to 25 pounds:

“I was heavy with Texas, but I was throwing well so it was fine. It’s fine until it’s not… I just wasn’t really moving fast. I wasn’t really moving clean or synced up or really doing anything right out there. I was just kind of willing it to get there instead of it feeling close, so just want the mound to feel close.”

According to the Arizona Republic’s Nick Piecoro, the Diamondbacks asked at least one team to take on $13 million of Montgomery’s remaining salary in a potential trade, but after finding no takers, they appeared on track to slot the lefty in long relief to open the season, with Pfaadt asserting his claim on the fifth spot in the rotation. However, just a day later, Montgomery revealed he would need surgery, telling reporters that he had been having trouble recovering from his starts after “probably just trying to throw too hard too soon.” He expected he might receive a shot following an MRI, but instead learned he had a significant UCL tear. Now he’s facing his second Tommy John surgery; he underwent his first in June 2018, when he was with the Yankees. Going less than seven years between surgeries feels like a rather shocking outcome for a pitcher who’s not an especially hard thrower; in all likelihood, Montgomery won’t pitch a competitive game again until mid-2026.

As for Pfaadt, the 26-year-old righty made his season debut against the Cubs on Saturday, allowing three runs in six innings while striking out five. He’s earning $799,400 this year; his five-year, $45 million covers the 2026–30 seasons, spanning not only his arbitration seasons but also his final year of pre-arbitration and his first of free-agent eligibility. He gets a $2 million signing bonus, and then will make $3 million for 2026, with subsequent salaries of $5 million, $8 million, $11 million, and $15 million. The contract also includes a $21 million club option with a $1 million buyout for 2031, then a $25 million mutual option for ’32. He’ll have a five-team no-trade clause for 2030–32 as well.

A fifth-round pick in 2020 out of Bellarmine University in Louisville, Pfaadt entered the 2023 season ranked 16th on our Top 100 list, a 55-FV prospect with four offerings — fastball, curveball, slider, and changeup — capable of missing bats. He debuted with the Diamondbacks on May 3, 2023, shortly after they cut bait on Madison Bumgarner. He was tagged for seven runs in 4 2/3 innings by the Rangers in his first outing, and bounced back and forth between Triple-A Reno and Arizona a couple times while getting similarly lit up; through his first six starts, he owned a 9.82 ERA and 7.46 FIP. Recalled again in late July, he pitched better; though his final numbers (5.72 ERA and 5.18 FIP in 96 innings) were still quite garish, he earned enough trust to claim a spot in Arizona’s postseason rotation. While he lasted five or more innings in only two of his five postseason starts, he put up a 3.27 ERA in 22 innings as the Diamondbacks won four of them — all but his World Series Game 3 start — during their unlikely postseason run.

Pfaadt spent all of last season in the rotation, leading the Diamondbacks in starts (32), innings (181 2/3), and WAR (3.1). His 4.71 ERA was the fourth highest of any qualified NL starter, but his peripherals suggest he pitched much better than that, with a 24.3% strikeout rate, 5.5% walk rate (fifth lowest in the league), and 1.19 homers per nine. Both his 3.61 FIP and 3.78 xERA were considerably lower than his actual ERA, with his 1.10 gap between his ERA and FIP the league’s third highest among qualifiers.

A closer look at Pfaadt’s performance reveals that his ERA and FIP were actually in reasonable alignment for the first two-thirds of the season:

Here’s what his splits look like:

Pfaadt struck out hitters with greater frequency over the last third of the season, but the hits fell in with absurd frequency, driven by a higher barrel rate:

As with his ERA and FIP, Pfaadt’s actual batting average and slugging percentage allowed tracked closely with his Statcast expected numbers over the first two-thirds of the season but diverged widely over the final third. All of this happened as he actually gained velocity with his four-seam fastball (from 93.5 mph to 94.5) and improved his stuff and location according to Stuff+:

For what it’s worth, Pfaadt’s PitchingBot splits didn’t show as much contrast. One thing that really does stand out from Pfaadt’s pitch splits is that despite the high grades for his slider (sweeper, according to Statcast) over both stretches, batters hit .170 and slugged .386 against the pitch through the season’s first four months, but improved to a .339 AVG and .643 SLG over the final two; his barrel rate more than doubled (from 8.1% to 16.7%) even as his whiff rate improved slightly (from 35.8% to 38%).

All of which is to say that Pfaadt may just have been experiencing a run of bad luck. Interestingly, Arizona’s BABIP allowed spiked from .300 through July to .328 thereafter even as the team surged and nearly snagged a playoff berth. After going 58-51 (.532) through July, the Diamondbacks went 31-22 (.585) the rest of the way, but wound up missing a Wild Card spot because of tiebreakers.

Because projection systems strip out the luck, Pfaadt is forecast to shave his ERA down to 3.94, with a 3.75 FIP. ZiPS likes him even a bit better than that (3.87 ERA, 3.62 FIP), so much so that he made Dan Szymborski’s Booms list, with Dan noting that Pfaadt improved his first-strike rate from 64% in 2023 to 71% last year. On the subject of ZiPS, here’s his projection for the contract extension:

The ZiPS suggestion for the first five years of that deal is $43.9 million, so this projection is literally just about right on the money. The Diamondbacks, whose $200 million payroll ($226 million for Competitive Balance Tax purposes) is a club record, will have considerable cash coming off the books after the season, with Montgomery, Gallen (who’s making just $13.5 million), and Kelly ($7 million) hitting free agency, along with Eugenio Suárez ($15 million) and Josh Naylor ($10.9 million). Pfaadt’s cost certainty and comparatively low salary should help provide some flexibility when it comes time to restock, ideally if he fulfills his potential as a mid-rotation starter.