So Far, So Good for the Blue Jays’ Next Great Bullpen Piece

Six months ago Spencer Miles was a name known only to prospect hounds and Giants player-development staff. After missing the entire 2025 campaign while rehabbing from Tommy John surgery, the right-hander had totaled 14.2 professional innings since signing in 2022, none above Low-A. Facing an uncertain future, Miles accepted an invitation to the Arizona Fall League, desperate for competitive innings. He responded with 8.2 frames across five outings, striking out 12 and flashing the kind of metrics that make scouts sit upright.

The performance forced a decision. San Francisco, already protecting a crowded 40-man roster, declined to shield Miles from December’s Rule 5 Draft. Toronto pounced on the final day of the Winter Meetings, betting that the stuff would translate in the big-league bullpen.

Miles arrived in Dunedin this spring competing with fellow Rule 5 pick Angel Bastardo and a handful of non-roster arms for one of the last relief jobs. The results were pedestrian, but the arsenal was not. Toronto kept the focus on the data—velocity, movement, deception—and awarded Miles a spot on the 26-man roster.

Five appearances and 9.1 innings later, the early returns are promising. The box-score numbers are solid; the underlying metrics are tantalizing.

What separates Miles is a four-pitch mix more common in a rotation than a bullpen. He pairs a riding four-seam fastball that sits 96-98 mph with a heavy sinker that averages 15.9 inches of horizontal break and approaches the zone at a steep -5.3-degree vertical angle. The sinker has already generated whiffs on 30 percent of swings despite finding the zone less than half the time.

His third offering is a gyro slider that behaves like a cutter, thrown at 87.4 mph with minimal vertical ride and late glove-side dive. Hitters have yet to record a hit off the pitch in five batted-ball events, and the whiff rate sits at 15 percent.

Miles rounds out the repertoire with a sharp 12-to-6 curveball that earned above-average grades in the AFL but has been punished early: both homers he has allowed came on hooks, and opponents own a .399 expected batting average and 1.367 expected slugging against the pitch. The curve is thrown almost exclusively to left-handed hitters (68.4 percent usage), an approach Toronto hopes will become less predictable as the rookie gains experience.

The learning curve is steep. Miles had never pitched above A-ball before debuting in the 11th inning of a tie game against Oakland and escaping unscathed. He now works in a bullpen governed by meritocracy for a club in win-now mode. If he falters, he must be offered back to San Francisco.

For the moment, the Columbia, Missouri native is thriving. The velocity is elite, the presence is calm, and the swing-and-miss ability is real. So far, so good for Spencer Miles—and for the Blue Jays’ gamble on the next potential bullpen cornerstone.