McClanahan was invited to the Rays' big-league camp, Marc Topkin of the Tampa Bay Times reports.
McClanahan has yet to reach Triple-A and has only made four starts at the Double-A level, so he's unlikely to be in consideration for an Opening Day roster spot. The 22-year-old struggled to an 8.35 ERA in those four starts for Montgomery, though his 2.50 ERA in 17 starts and two relief appearances at the Low-A and High-A levels was quite strong.
McClanahan tossed five scoreless frames while working around two hits and a walk and striking out eight Friday in his debut for Double-A Montgomery.
The 2018 first-round pick earned a move up to the Southern League after submitting a 1.46 ERA, 0.84 WHIP and 59:8 K:BB across 49.1 innings with High-A Charlotte. Barring a catastrophic injury or a complete collapse in his first taste of Double-A, the 22-year-old lefty should head into 2019 as a consensus top-10 prospect within a robust Tampa Bay system.
McClanahan has posted a 0.31 ERA in five starts (29.1 innings) since being promoted to High-A Charlotte.
Drafted last year with the 31st overall pick, McClanahan joined his first full-season affiliate to begin 2019 and needed only 11 appearances to earn a promotion to High-A. He seems ready for another new challenge. Overall, McClanahan has a 106:35 K:BB and .184 BAA in 82.1 innings. The 22-year-old lefty has a good fastball and two viable secondaries, with decent command. He's among the more notable prospect risers on the pitching side this season.