Kloffenstein signed for an above-slot $2.4 million bonus as the 88th overall pick in 2018 from the Texas prep ranks. He was very young for his class, still 17-years-old when he turned pro and still just 18 for most of his first full season. I got a look at the big righty during Extended Spring Training, and came away impressed with his mix of physicality, stuff, and pitching IQ.

Kloffenstein looks all of his 6-foot-5 and 243-pound listing. He’s an imposing figure on the mound with advanced durability for a pitcher this age, albeit in a frame that’s similarly more mature than most teenagers. He gets through a low maintenance semi-windup fairly easily, with moderate effort that projects to clean up a bit with more time at the professional level. The fastball touched 96 mph in my look, sitting at 92-to-93 mph with consistent angle and armside run. Kloffenstein showed a polished ability to mix grips on his heater, mixing four-seam and two-seam variants to stay off barrels. His main off-speed is a mid-80s slider that flashed hard gloveside action at best, showing the makings of a definite future big league pitch. It was enthusing to see a pitcher this age show feel over a true four-pitch mix, as Kloffenstein also wrinkled in a curveball (76-77 mph) and changeup (85-86 mph) that both showed glimpses of promising action. Just as impressive was his mound presence, pitching with a competitive fire even in a backfields intersquad game and drawing high praise from coaches for his on-field makeup.

The ninth overall prospect on our rundown of Toronto’s top prospects this off-season, we placed Kloffenstein fairly high in a deep system considering he has yet to develop much pro track record. The Blue Jays are understandably bringing him along slowly, and even if it takes another year or so, this is the type of arm that can really break out in full-season ball—especially if his velocity takes a jump forward. Kloffenstein has the makings of a solid big league starter with continued development of his changeup and off-speed execution.