A true three-sport athlete, Middleton was drafted out of junior college as a projectable athlete with high upside but that did not manifest itself on the baseball diamond...until this year. Middleton struggled as a starter for his first three seasons (47 starts of 5+ ERA across Rookie and A-ball), so the Angels converted him to a reliever and he has looked every bit like the big league contributor evaluators once envisioned. In 46 appearances this year, Middleton threw 66 innings with a 3.41 ERA, 1.136 WHIP, and a 3.14 K/BB across high-A, AA, and AAA.
Middleton’s breakdown of his performance by level shows maturity and progression, as he finally figured out his command at AA and AAA, the upper most levels of the minors. It’s a small sample size, but his low walk rates (2.45 BB/9) and low HR rates (0.6 HR/9) in AA and AAA make him an athletic, talented reliever with oodles of upside. His velocity went up from low-90s as a starter to now mid-upper 90s as a reliever, with his four-seamer sitting in the 96-99 range, often touching triple digits and once touching 102 mph. This sets up his offspeed well, and he uses his two-seam fastball for late-run. His slider is reportedly very, very good when he can command it, which he did at the upper levels of the minors this year. In relief capacity, he rarely throws his changeup and curveball as those pitches need more development before they are used regularly in in-game situations.
Middleton has the potential to be the setup man or closer if his improved command is the real deal, and even if he doesn’t he profiles as a reliable middle relief option. Expect to see him next season in some capacity. With the volatility of Angels relievers, Middleton might even make the big league team out of Spring Training and get his first taste of the majors. Don’t let the 40/45/50 overall grade fool you: although relievers are graded more harshly since they pitch less, Middleton has the stuff to be one of the better ones on the Angels’ 2017 squad with a chance to be much more.