Royals Prospect Brennon McNair's Impressive Power Surge

It’s been a slow road forward for Kansas City Royals’ prospect Brennon McNair. McNair was selected by the organization in the 11th round of the 2021 Amateur Draft. At the time, the Royals paid McNair $347,000 to sign out of high school. He debuted that same year, appearing in ten games for the Surprise Royals in the Arizona Complex League. Kansas City sent him back to the level in 2022, where across 42 games, McNair showed strong power potential as a 19-year-old. He slashed .231/.322/.429 that year in the Complex with a .199 ISO.

The showing earned McNair a promotion to Low-A Columbia to open the 2023 season. He stayed there all season and struggled immensely. In 70 games, McNair posted an 81 wRC+ with a .293 slugging percentage and an awful 38.3% strikeout rate. Then this season, McNair returned to Columbia and was better — but still not great. He finished 2024 with a 99 wRC+, a .191 average, and a 33.4% strikeout rate. Those contact numbers must improve for McNair to succeed, but the blossoming power output is certainly noticeable.

McNair finished his 2024 season with a career-high eight home runs. After the season, he set off for Australia. In the Australian Baseball League this winter, McNair has continued to experience a power surge. For the Brisbane Bandits, McNair has swatted seven more home runs in just 23 games. The level of talent in the ABL isn’t near the same talent as McNair will face back at home, but a .538 slugging percentage is nothing to scoff at. What changed?

Comparing 2023 to 2024, there are some slight tweaks to McNair’s stance at the plate. In 2023, he was more upright at the plate, utilizing a slightly closed stance. In 2024, the stance straightened up a bit and McNair dropped his stance slightly, bending his knees. Could those small tweaks impact McNair’s power output enough to make a difference? Those changes alone, probably not. However, how the tweak impacts the rest of his swing seems to be making a noticeable impact.

Above is a full swing from McNair in early 2023 with the Fireflies. The upright stance is apparent. As McNair steps into his swing mechanics, he drops his upper half and bends his knees. That motion created a bit of a hitch in his swing, dropping his hands before pulling them back and then moving into his swing. It all came together in quite a few moving parts resulting in a greater margin of error with timing as well as an overall lack of consistency.

The 2024 changes to McNair’s swing lessened that hitch and simplified his swing mechanics. It looks to have essentially split his swing mechanics in half. Now, McNair looks to start low in his stance before stepping into his swing and allowing his lower half to remain more on time. That lower half in particular seems to be the key to the recent power surge.

Here’s the full swing from 2024. It’s a more fluid swing with fewer moving parts. McNair can focus more on his timing and less on keeping his busy upper half in tune with his lower half. There’s still some twitch with his hands, but that’s what allows McNair to load his power. The raw power potential was never so much the question as was the timing and ability to get into that strength. In Australia, the impacts of the tweak are even more apparent. McNair has exploded with a .538 slugging percentage in 23 games. He leads the league with seven home runs and his slugging percentage is fourth among hitters with at least 50 at-bats.

Again, it’s the lower half for McNair. Once again on the right is McNair in 2023 with the right image showing McNair in this winter’s Australian League. He’s more drastically changed his swing mechanics to get into his lower half and transfer more power into his swing. The hands have dropped further, really enhancing the changes we’ve seen from McNair. Those changes continue to allow him to find more power output. Bringing it back to the states next season will be key, as will a better ability to make contact.

The latest tweaks from McNair have helped him to rediscover the power ceiling that once made him an intriguing young prospect. The strikeout rate remains far too high even in Australia, however, and he’s hitting just .238. Further development remains to be seen in that regard, but McNair should at least be back on the map as a notable prospect in the Royals’ system. He’s transferred to left field more often than anywhere else in the field, offering a plus arm with above-average power from the corner outfield.

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