Royals’ James McArthur Placed On Injured List

2:45pm: The Royals have placed McArthur on the 15-day IL with a right elbow sprain, recalling right-hander Steven Cruz in a corresponding move.

11:43am: Royals reliever James McArthur exited last night’s game due to elbow tightness, the team announced. He’s undergoing testing today to determine the source of the discomfort and the severity of any potential injury, per Anne Rogers of MLB.com.

McArthur initially looked to have suffered a hand injury when covering first base on an infield single off the bat of Zach McKinstry, but manager Matt Quatraro tells Rogers that wasn’t the issue. McArthur stayed in to face the next batter after McKinstry reached but shook his arm after missing badly off the plate on a fastball to Jake Rogers (video link). He began to set for his next pitch, but catcher Salvador Perez called for the training staff after seeing his right-hander shake that arm. Per Quatraro, McArthur acknowledged that “something felt off” in his arm, and he quickly departed with trainer Chris DeLucia.

The 27-year-old McArthur opened the 2024 season as the Royals’ closer and still leads the club with 18 saves, though he’s since ceded ninth-inning duties to deadline acquisition Lucas Erceg. That switch was borne both out of both Erceg’s excellence and a midseason rough patch for the hard-throwing McArthur. After a couple of rocky appearances to begin the season, McArthur found his groove and rattled off 36 2/3 innings of 3.22 ERA ball from April 5 through July 23. Those are arbitrary endpoints, of course, but it’s roughly half a season’s worth of quality bullpen work from a pitcher who’d been trusted with the highest-leverage role in Quatraro’s bullpen.

McArthur, however, was shelled for eight runs over his next two appearances on July 24 and 28. The Royals acquired Erceg from the Athletics two days later. McArthur has pitched primarily in a middle relief role since and has a 3.77 ERA in 14 1/3 innings in that span, with the bulk of the damage against him coming in one brutal day at Yankee Stadium. Overall, McArthur has a 4.92 ERA on the season, although that number is skewed heavily by his past six weeks or so of tumultuous performance.

There hasn’t been a pronounced drop in McArthur’s velocity, although his sinker is down a bit in recent outings. He averaged 95.1 mph on the pitch through the sixth of September but has seen the pitch clock in at an average of 94.3 mph across his past three appearances. McArthur has had similar dips in velocity throughout the year, so it’s not necessarily alarming in isolation, but any change in stuff/velocity when coupled with arm discomfort is a red flag.

The Royals are already without deadline pickup Hunter Harvey (back strain) and veteran free-agent signees Will Smith (back spasms) and Chris Stratton (flexor strain). Erceg, John Schreiber and former starters Kric Bubic and Daniel Lynch IV are among the top options left in an increasingly injury-marred Kansas City bullpen.