A former fourth-round pick out of the New Hampshire prep ranks, McKenna burst onto the scene in 2018 with a scorching first half in the Class A Advanced Carolina League (.377/.467/.556), earning a promotion to Double-A that summer. He had a tougher go of it in the Eastern League (.239/.341/.338), but put together a strong showing in the Arizona Fall League (.344/.474/.590) before stagnating a bit in his second crack at Double-A (.232/.321/.365) in 2019.
Still, McKenna impressed the Orioles enough for them to protect him from the Rule 5 Draft last November. He’s a plus runner with sneaky power who has made stealing bases a major part of his game, though efficiency (25 in 36 attempts) was an issue last year at Bowie. McKenna is extremely athletic but probably needs to make more contact to fully tap into what right now is a gap-to-gap offensive profile.
Defensively, the way McKenna blends his speed with an above-average arm and good instincts lead many to believe he can stick in center field long-term. He has the ceiling of an everyday player at the position whose motor allows him to hit at either the bottom or top of the order, and the floor of a versatile fourth outfielder who makes an impact off the bench and late in games. Improved consistency, though, will go a long way toward determining what kind of role McKenna ultimately falls into.
Scouting grades: Hit: 55 | Power: 40 | Run: 60 | Arm: 50 | Field: 55 | Overall: 45
A product of the New Hampshire prep ranks, McKenna was committed to Liberty before the Orioles drafted him in the fourth round and signed him for slot value. He showed well in his first full season, tallying 42 extra-base hits and 20 steals at Class A Delmarva, and then broke out in earnest in 2018 with a torrid first half in the Class A Advanced Carolina League (.377/.467/.556) before a bump up to Double-A in June. While he didn't fare as well in the Eastern League (.239/.341/.338), McKenna did get back on track in the Arizona Fall League, finishing fifth in the batting race (.344) and second in OPS (1.064).
McKenna's quick bat and natural feel for finding the barrel helps him make consistent line-drive contact, and he's become increasingly comfortable hitting to all fields as he's faced better pitching. He's also made strides in refining his approach, demonstrating a combination of patience and aggressiveness that fuels his ability to both hit for average and get on base at a solid clip. While McKenna projects for more gap power than true over-the-fence pop, some evaluators believe he could have seasons with double-digit homers in his prime.
McKenna gets out of the box exceptionally well for a right-handed hitter and routinely posts plus-or-better home-to-first run times. That speed also gives him the chance to stay in center field, and he has more than enough arm strength for the position. Overall, McKenna has the ceiling of a center fielder who hits at either the top or bottom of the lineup, and his well-rounded game gives him a realistic fourth-outfielder floor.
Scouting grades: Hit: 55 | Power: 45 | Run: 60 | Arm: 50 | Field: 50 | Overall: 50
Hailing from St. Thomas Aquinas in Dover, N.H., McKenna didn't receive a lot of Draft exposure until temperatures began to rise in the Northeast. The Orioles liked what they saw in McKenna, ultimately drafting him in the fourth round in 2015 and signing him for full slot value. He had a promising full-season debut in 2017 with Class A Delmarva, posting a .712 OPS with 42 extra-base hits and 20 steals, and continued to build on that performance in '18 with a superb first half in the Class A Advanced Carolina League -- he ranked among the circuit leaders in most offensive categories -- that earned him his first Double-A promotion in June.
McKenna has good feel to hit, with a line-drive approach that produces quality contact from line to line. He has sneaky pop for his size, too, and some evaluators believe some of McKenna's doubles will eventually translate to more home runs. His overall approach is solid, albeit with some swing-and-miss tendencies. McKenna has very good speed from the right side of the plate and is a threat on the basepaths. That speed also gives him the chance to stay in center field, and he has more than enough arm strength for the position.
As with many high schoolers from cold-weather states, patience will be key with McKenna. He's rewarded the Orioles so far with his improvements in each season, and if all goes as hoped, he could develop into a toolsy, up-the-middle player capable of hitting atop the lineup.