Born and raised in Morgan Hills, California, Aidan Keenan grew up playing baseball with his older brother, Tyler, who eventually went on to be selected by the Seattle Mariners in the fourth-round of the 2020 MLB Draft out of the University of Mississippi. Aiden was just as good, but unlike his brother, he shone on the mound rather than at the plate. In addition to playing basketball and football, Aiden was a three-year letterman at Live Oak High School, winning the 2021 Blossom Valley Athletic League Sophomore of the Year Award and the 2023 Blossom Valley Athletic League Pitcher of the Year Award, in addition to others. In his senior season, he posted a 0.74 ERA in 47.0 innings with 75 strikeouts, and was considered one of the better prep players in California available in the 2023 MLB Draft, but had a very strong commitment to Stanford and withdrew from the 2023 draft class.
The right-hander did not see much action in his freshman season. All in all, he appeared in 5 games for the Cardinals, starting 2, and allowed 5 earned runs in 6.2 innings, resulting in a 6.75 ERA, allowing 4 hits, walking 10, and striking out 7. When he returned to Stanford in 2025 for his sophomore season, coach Esquer decided to use Keenan exclusively out of the bullpen, and the right-hander had a bit more success. Appearing in 24 games, he posted a 5.59 ERA in 37.0 innings, allowing 33 hits, walking 14, and striking out 43. That summer, Keenan played for the Santa Barbara Foresters of the California Collegiate League and looked good in the pair of games he started.
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A junior for the 2026 season, coach Esquer moved the right-hander into the Cardinals’ starting rotation, but an oblique injury in mid-March cost him the majority of the season. In five starts in February and March prior to the injury and two more in May after returning from it, Keenan posted a 5.82 ERA in 21.2 innings, allowing 22 hits, walking 21, and striking out 25. Following the conclusion of the NCAA season, the right-hander appeared in a pair of games for the Falmouth Commodores of the Cape Cod Baseball League.
The 6’2”, 200-pound right-hander throws from a low-three-quarters arm slot using a high-tempo delivery that has a bit of effort to it.
Keenan’s fastball sits in the mid-90s, reportedly topping out as high as 99 MPH. Coupled with the riding life that the pitch has, the pitch has the potential to be a well above-average offering, but on the whole, the pitch grades down because the right-hander does not have the best command of it.
The right-hander complements it with a sweeping slider, a cutter, and a changeup. His slider is the best of the three, a mid-80s, high-spin offering that features a tight vertical drop and impressive horizontal movement. His cutter, which sits in the high-80s, has tighter horizontal hop, but has been effective in inducing weak contact. Keenan throws two variants of his changeup, a high-80s circle changeup with more run and a low-80s split changeup with more vertical drop, but both variants are still developing and are only occasionally used during in-game situations.
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As mentioned, Keenan has poor command not just of his fastball, but of all of his pitches. When he is on, he is more of a control-over-command pitcher, where he is still hitting the strike zone despite not hitting his spots, but when he begins tiring and losing stamina, he starts losing the entire strike zone.
