The Rays made a surprising addition to their postseason roster on Tuesday, calling up 23-year-old left-handed pitcher Shane McClanahan ahead of the team’s Wild Card Game 1 matchup against Toronto.

Ranked No. 99 on MLB Pipeline’s Top 100 Prospects list and No. 6 on the Rays’ Top 30, McClanahan, who reportedly has been pitching well at Tampa Bay’s alternate training site since returning from a hyperextended knee that sidelined him for several weeks in early September, was one of the organization’s more impressive prospects this year during Spring Training and continued to open eyes with a strong performance during Summer Camp. He’s expected to be used out of the bullpen by the Rays in the postseason.

Selected by the Rays in the first compensation round (No. 31 overall) of the 2018 Draft, McClanahan missed all of 2016 after undergoing Tommy John surgery as a South Florida freshman, but he returned the following year to post a 3.20 ERA with 104 strikeouts in 76 innings. He was even better as a redshirt sophomore the following year, with reports from early in the spring noting that the southpaw’s fastball was pushing triple digits. He ultimately racked up 120 strikeouts in 76 1/3 innings for the Bulls to finish second in the nation in strikeouts per nine innings (14.1), though control issues (5.7 BB/9) hurt his Draft stock in the eyes of some evaluators.

The Rays, however, saw a unique chance to land a powerful and projectable arm and signed McClanahan for $2.23 million, a tad above his slot’s recommended value of $2.22 million. He rewarded the organization with an impressive performance during an abbreviated pro debut after signing, then put himself on the Major League radar in earnest by climbing three levels up to Double-A Montgomery in his first full season.

After beginning the 2019 season at Class A Bowling Green, where he posted a 3.40 ERA with 74 strikeouts in 53 frames en route to midseason All-Star honors in the Midwest League, McClanahan received a promotion to Class A Advanced Charlotte in early June and went 6-1 with a 1.46 ERA and 59/8 K/BB in 49 1/3 innings, making eight starts. That performance prompted the Rays to bump McClanahan up to Double-A in August, and while his performance (8.35 ERA in four starts) with the Biscuits left something to be desired, the quality of the left-hander’s stuff was still plenty good.    

That was also the case this past spring in McClanahan’s first big league camp, when he posted a 12.00 ERA while appearing in six games (one start) for the Rays. But he still racked up 11 strikeouts in six innings, while flashing an assortment of powerful, swing-and-miss stuff that only furthered the belief among Rays officials that the team could use McClanahan out of the bullpen at some point during the 2020 season.

Here's our breakdown of McClanahan’s tools on the 20-80 scouting scale, where 50 represents big league average ability:

Fastball (65): While the 100-mph heater McClanahan flashed at South Florida represents his peak velocity, the athletic southpaw does throw very hard consistently, sitting in the mid-to-upper 90s with his heater. The pitch plays up due to its late life, which in turn helps McClanahan get whiffs in the zone, and it's possible that he’ll throw harder working in short bursts out of the bullpen than he has in the past as a starter.  

Slider (60): McClanahan’s breaking ball is a true weapon, and while the action he imparts makes it more of a slurve than a true slider or curveball, he’s proven to be adept at manipulating the pitch’s spin in order to give it a different look. The best version of McClanahan’s breaking ball comes when the left-hander throws it with a hard, slurvy shape and sharp bite, but he also has enough feel that he’s able to morph the pitch into more of a traditional curveball, thrown with more downer action than side-to-side movement. Regardless of which version McClanahan deploys, it consistently plays as a plus pitch.

Changeup (50): McClanahan’s changeup lags behind his other two offerings right now, though he also has had less time to develop the pitch early in his pro career than he has his fastball and breaking ball. That said, Rays officials expect McClanahan to eventually have an average changeup, giving him a useful third pitch that he can use to combat right-handed hitters, though it may take a backseat to his fastball-slider combo in a bullpen role.

Control (45): McClanahan is more of a power pitcher than he is a strike-thrower right now, and his overall fastball command requires more refinement. But there’s something to be said about the left-hander’s natural bat-missing ability, a trait that could become amplified in short bursts out of the bullpen, and he’s never shied away from attacking hitters on both sides of the plate with his premium stuff.