Arbitrary Thoughts: James McArthur Could Boost the Royals Bullpen in 2027

 James McArthur – Right-Handed Relief Pitcher

Age on 2027 Opening Day: 30
Service Time: 2.150

2024 Salary: $745,750
2025 Salary: $773,750
2026 Salary: $810,000 (First Year of Arbitration)
2027 MLB Trade Rumors Projection: $800,000

McArthur's Background

The Phillies drafted McArthur in the 12th round out of Ole Miss in the 2018 MLB Draft. He gained notoriety as a tall pitcher (6'7) with a big arm who could, at the very least, find a spot in a Major League bullpen. 

With the Phillies, McArthur got on prospect experts' radars with a solid 2021 Double-A campaign. In 19 games (15 starts) and 74.1 IP, he posted a 4.48 ERA, 4.24 FIP, 1.30 WHIP, and 17.2% K-BB%. While he wasn't a big strikeout guy (24.4% in 2021), he limited walks (7.2% BB%) and induced ground balls (48.3% GB%). As a result, MLB Pipeline ranked him the Phillies' 20th-best prospect in 2022, ahead of Christopher Sanchez (ranked No. 22 at the time). 

Here's what Pipeline said about the former Ole Miss product in their 2022 scouting report:

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After spending three years as part of Mississippi’s rotation, McArthur became a 12th-round Draft pick of the Phillies in 2018, getting an over-slot $215,000 to keep him from going back to Ole Miss for his senior year. He started and relieved in his first full season and spent most of the 2021 season starting in a hitting-friendly home park in Reading. He added innings in the Arizona Fall League and while he was inconsistent there, he finished well and showed enough to earn a spot on the Phillies’ 40-man roster.

McArthur still has the four-pitch mix and the size (6-foot-7) that made the Phillies like him in the first place. He was throwing his fastball in the 92-95 mph range, sometimes touching 96, with some sinking action to it during his AFL stint. Making some adjustments to how he grips his slider has allowed him to add more sweep to it, an above-average breaker that has the chance to be a consistent swing-and-miss pitch for him. He still has the slower curve and a changeup, both of which he uses more against left-handed hitters.

McArthur struggled in a repeat in Double-A Reading in 2022, posting a 5.05 ERA and 4.99 FIP in 13 starts and 57 IP. After making four more starts in 2023 with Triple-A Lehigh Valley, the Phillies traded McArthur to the Royals for outfield prospect Junior Marin and cash considerations. 

The Royals quickly moved McArthur to the bullpen, and he found success at both the Minor-League and major-league levels.

In 23 appearances and 40.2 IP with the Storm Chasers in 2023, he posted a 3.98 ERA, 3.57 FIP, a 1.28 WHIP, and 19.9% K-BB%. His K% rose to 31.5% in Omaha, and he maintained a solid 48.4% GB%. As a result, the Royals promoted McArthur to the Majors, and despite a rough debut (he gave up seven runs on six hits and one walk in an inning of work against the Guardians), he ended up being the Royals' closer by the end of the 2023 campaign.

In 23.1 IP, McArthur posted a 4.63 ERA. However, his FIP was 2.78, with a 0.94 WHIP, 25.6% K%, and 23.3% K-BB%. Furthermore, many of his Statcast percentiles were eye-popping for a rookie, as shown below via TJ Stats. 

After a stellar 2023 stint, the Royals put him in high-leverage early in 2024, and he started the year well. He posted a 2.63 ERA and 1.63 FIP through April 30th, which included seven saves and a 23.2% K-BB% over 13.2 IP. Unfortunately, he struggled with consistency for the remainder of the season.

In 56.2 IP, he posted a 4.92 ERA, 4.17 FIP, and saved 18 games. He was particularly hurt by a high BABIP (.347), low strand rate (66.7% LOB%), and high HR/FB% (16.7%). On a positive note, he still generated a lot of groundballs (53.3% GB%), his FIP was lower than his ERA, and while his batted-ball percentiles weren't great, his strike-based ones were much more encouraging.

McArthur's season ended after his September 16th outing when he hit the IL with a grade 1 right UCL sprain and missed the rest of the season (and the postseason). He then ended up getting right elbow olecranon surgery to repair a fractured elbow, which would sideline him for most, if not all, of the 2025 season.

While the Royals didn't expect much, if any, time from McArthur in 2025, recovery complications ultimately cost him the 2026 season. During his recovery, doctors discovered that McArthur suffered an allergic reaction to the metal screws inserted during his elbow surgery. This required a second procedure to remove the hardware. As a result, he missed nearly all of last season to recover from the surgery and cleanup procedure.

On a positive note, he returned at the end of 2026 for a rehab assignment in Triple-A Omaha. He made four appearances and pitched 3.2 innings with the Storm Chasers. The stats weren't good (7.36 ERA and 7.68 FIP), but he showed solid stuff, a groundball rate, and the ability to extend in his first appearance on the mound in nearly two years.

The Royals called him up to the active roster for the final game of the year, but he didn't appear in the season finale. McArthur is expected to be fully healthy and ready for Spring Training. 

2026 Stats

4 G, 3.2 IP, 7.36 ERA, 7.68 FIP, 1.36 WHIP, 0.0% K-BB% (Triple-A Omaha). 

Royals Relief Pitcher Depth

• 40-man roster: Steven Cruz, Jose Cuas, Connor Thomas, Carlos Duran, Beck Way, Nolan Hoffman, Spencer Bivens
• Arbitration Eligible: Nick Mears, Daniel Lynch IV, Lucas Erceg, Anthony Gose
• 2027 Club Option: Carlos Estévez
• Triple-A: Tyson Guerrero, Augusto Mendieta, Shane Panzini, Luke Little, Ben Sears, Chazz Martinez, Brandon Johnson, Oscar Rayo

Why the Royals Should Offer Him Arbitration

Because McArthur missed two full years at the Major League level, he will come cheap in arbitration. According to MLB Trade Rumors, his projected arbitration amount is $800,000, $10,000 less than a year ago. For context, Mears ($2.2 million), Alex Lange ($1.7 million), and Alec Marsh ($1.1 million) were expected to command higher amounts this offseason. McArthur is not only cheaper than those three, but he's also more likely to be healthier and/or more effective.

While McArthur posted high ERAs in 2023 and 2024 with the Royals, his FIP numbers suggested he's a much better pitcher. The now-30-year-old righty probably isn't a fit for closing situations anymore, but his stuff, ability to generate CSW (31.9% career CSW%), and groundball-inducing style make him an ideal low- to medium-leverage arm who can eat the middle innings. 

Even in a small sample, McArthur showed decent stuff last year, with his curveball rated as a pretty plus pitch based on TJ Stuff+ and grade numbers. 

Obviously, McArthur's chase, zone, and whiff rates were all below average in 31 pitches of cup-of-coffee in Omaha. However, this rehab stint was more about process than results. The velocity was fine, the movement was better-than-expected, and he actually did a decent job of limiting hard contact based on xwOBACON (.297).

Last year in Omaha, his curveball and slider posted TJ Stuff+ marks of 104 and 100, respectively. His breaking balls have a history of success at the Major League level. In 2024 with the Royals, he posted TJ Stuff+ marks of 110 and 101 on his curve and slider, respectively, and his chase and whiff rates were impressive on those pitches as well, as illustrated below.

The Royals need cheap relievers with good stuff to add depth. They also need relievers with Minor League options. Thankfully, McArthur checks off both those boxes. 

Why the Royals Should Non-Tender Him

McArthur has been hurt for two years, and guys who miss that much time can be unpredictable. Kansas City has already decided not to risk Marsh, who has also missed the past two seasons with various shoulder injuries. Considering the number of Royals pitchers on the 40-man roster already expected to miss significant time in 2027 (Cole Ragans, Luinder Avila, and Stephen Kolek), the Royals may feel that McArthur is too much of a risk to bring back, even if there's some upside there. 

Another issue with McArthur is that he seemed to hit a wall from May through the end of 2024. He went from a promising long-term closer (who can forget McArthur's 9th Infantry Raygun shirt) to a guy only pitchable in mop-up situations. At 30, the Royals may feel more comfortable giving a younger arm with more long-term upside a roster spot than McArthur. 

Prediction: The Royals Tender McArthur A Contract

With Marsh and Lange already gone, McArthur will likely return to Kansas City for at least one more year. There are too many reasons to keep him: his $800,000 projected salary barely dents the payroll, he still has a Minor League option, and he's shown enough to succeed at the MLB level. 

Now, just because the Royals tender McArthur a deal doesn't mean he'll stay on the Royals roster all of 2027 or even stay on the 40-man roster after Spring Training. If McArthur struggles in Spring Training, he could be a roster casualty, especially if a non-roster invitee shows he could earn a roster spot. With 2027 being a crucial year for this organization, they need pitchers they can depend on, and I'm not sure the Royals feel 100 percent confident in McArthur just yet after his long layoff. 

Still, the former closer deserves a spot in Spring Training to show what he can do. He has the profile to be a key part of this Kansas City bullpen in 2027, and he could slide into higher-leverage situations if he stays healthy and productive early in the season. His breaking balls (curveball and slider) have always rated well, and there's no reason to think they won't still be effective in 2027. 

It's totally plausible to experience a similar turnaround to Taylor Clarke in 2025. Clarke was a much-maligned Royals reliever in 2023 who returned in 2025 and produced a productive campaign in Kansas City. A similar success story could be due for "The General" in the upcoming season.  

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