Bullpen usage over the last two seasons has come to define the modern era of baseball.

Last season, three teams — the Rays, Angels and Blue Jays — logged over 700 innings with relievers. Just three seasons ago in 2016, no team eclipsed 600 innings. And the uptick in usage is not concentrated to a handful of teams. In 2015, 11 teams logged less than 500 innings with their bullpen, compared to zero in 2019.

The Cubs have been a part of the trend as well, increasing their bullpen usage by over 15% when comparing 2016 to 2019. 

While year-to-year fluctuations in a team’s bullpen usage may spike due to the quality of their starting pitchers in a given season, the overall trend confirms relievers are becoming a greater part of the equation with openers and early hooks from managers. This has a great effect on how pitching prospects are evaluated. Pitchers who would have been considered fourth or fifth starters in the past now have a greater chance of becoming multi-inning relievers.

Tyson Miller, the Cubs 2016 fourth-round pick, has been a starting pitcher for the majority of his minor league career, but the league-wide bullpen innovation could have implications on his future role. 

In 2016, the Cubs selected 16 college pitchers with their first 18 picks in the draft. Miller, a division-II right-hander out of California Baptist University, was the team’s second selection that June. He immediately became the highest draft selection in the university’s history, beating out 7th-round pick Trevor Oaks in 2014.

While the list of former division-II players with MLB careers is short, the names are impressive: J.D. Martinez, Sergio Romo and Nick Markakis, to name a few. Miller’s division-II career ended with a 2.71 ERA and 1.14 WHIP across over 270 innings, but what put Miller on radars perhaps more than anything was a stellar 2015 in the Cape Cod League. He threw 25 innings and struck out 29 batters, walking only 6 and posting a miniscule 1.44 ERA for the Brewster Whitecaps. His performance against better competition than he had faced in college vaulted him into the top-150 overall picks.

Miller’s professional career started right after his selection in 2016. He threw at the rookie level in Arizona before proceeding to Class A short-season for two appearances before his season ended. 2017 came with a full-season assignment to Class-A South Bend. Miller posted a worse-than-average 4.48 ERA across 120.2 innings with just 99 strikeouts.

His following year at High-A Myrtle Beach, however, showed marked improvement. He led the High-A Carolina League in WHIP, strikeouts and opponent average, showing the dominance of his season despite a modest 3.76 ERA. In 2019, Miller pitched primarily at Double-A Tennessee before a late-season promotion to Triple-A Iowa. He cruised through the first half of the year, but struggled after his promotion — a product of both a slight velocity decrease and the extra-lively ball in Triple-A. 

Miller’s repertoire consists of a four-seam fastball that sits 90-93 mph and tops out at 95. He used to throw a two-seam fastball but shelved it shortly into his minor league career. The quality of his current fastball has been praised for Miller’s innate ability to manipulate the pitch. He possesses above average control of the offering, and cut, sink and ride the pitch seemingly at will.

His primary off-speed pitch is a lateral slider, with sharp movement to his glove side. Miller’s near side-arm delivery creates even more trouble for right-handed hitters attempting to pick up the pitch’s spin out of his hand. He also throws a changeup primarily to left-handed hitters which some project to be an average pitch at peak. During 2018 spring training, Miller learned a new grip for the pitch and even tinkered with a spike-grip curveball. In an interview with The Athletic’s Sahadev Sharma, Miller suggested his troubles were location based at Triple-A in 2019, not pitch based. Prominent prospect analysts echo the same sentiment — Miller’s stuff is major-league quality. 

That brings us to what Miller’s ultimate role will be at the major league level upon his arrival. The cubs officially added him to the club’s satellite roster in South Bend Thursday. He has also been on the team’s 40-man roster since last winter, suggesting a promotion this season isn’t out of the picture. With Alec Mills and others vying for the rotation spot vacated by José Quintana’s injury in the short-term, the Cubs still have options like the evolving Tyler Chatwood to provide quality major league innings. Miller’s road to a starting pitcher job might be winding, but his skill set positions him well for a more-likely multi-inning relief role. His changeup allows him to circumvent issues for some pitchers presented by the three-batter minimum, and the diversity of his fastball allows him to provide multiple looks to hitters, even if he has to turn over a lineup.

Whatever Miller’s role, even as the landscape of pitcher usage evolves year to year, Miller has a place on the Cubs’ roster and an opportunity to make an impact.