Many of the data-driven revolutions in baseball are difficult to spot with the naked eye. It’s difficult for the average fan to pick up a launch angle adjustment in a hitter or higher spin rate on a curveball out of a pitcher’s hand.

Apart from shifting, one of the more noticeable trends is the increase in pitchers shortening their arm actions. The White Sox’s Lucas Giolito is a prime example. He shortened his arm action and kept the ball closer to his right pectoral muscle throughout his delivery as opposed to reaching back well beyond his hip. He went from a starter with a walk rate north of 11% and an ERA above 6.00 to a 5-WAR pitcher in one offseason. This trend has sprung up in other pitchers as well — the Dodgers’ Joe Kelly, the Reds’ Trevor Bauer, the Indians’ Shane Bieber and even this season, the DBacks’ Robbie Ray.

If you were aware of this trend, something may have looked familiar when Jason Adam stepped to the mound Sunday for his debut with the Cubs. Apart from Craig Kimbrel hovering parallel to the ground and swinging his arm, there may not be a more distinct characteristic of a Cubs pitcher’s delivery than the short arm action of Adam.

The 2010 5th-rounder has had a winding road to the major leagues. The Royals initially drafted him and kept him in their system for three seasons before trading him to the Twins in 2014. Adam missed the entirety of 2015 and 2016 with stress fractures in his arm, and upon his return to the mound, he signed with the Padres before returning to the Royals in late 2017. The Royals then traded Adam again — this time to the Blue Jays early in 2019, who non-tendered Adam at the end of last season.

The Cubs signed Adam to a minor league contract in January. When the team placed Tyler Chatwood on the 10-day IL Sunday, they recalled Adam from the South Bend player pool and he immediately saw time in the Cubs’ 6-5 loss to the Brewers. 

Adam’s repertoire on the mound is enticing. He features a high-spin fastball that touched 96.8 mph on Sunday, with a devastating changeup and sharp curveball. On 25 pitches, he generated five whiffs, a swinging strike rate that, if he sustains it, would place him in the 97th percentile in baseball among relievers on that metric.

Perhaps more impressive is that Adams generated whiffs on each of his three pitches, whereas many high-whiff relievers rely on two pitches to do damage, like Kimbrel’s fastball and knuckle curve pairing. And between Dillon Maples and Adam, the Cubs also roster two of the top 15 pitchers in average four-seam fastball spin rate. 

While his role in the Cubs bullpen is somewhat undefined, his skillset is a mix of outlier characteristics — from his short, deceptive arm action to his elite spin fastball and wiffle-ball changeup — could find a home in high-leverage situations alongside Rowan Wick and Jeremy Jeffress.