Drafted 28th overall out of Walton High School in Marietta, Georgia in 2016, Kieboom’s steady rise through the minors gave Nationals fans and card collectors alike reason to be optimistic about the short stop’s future. Kieboom debuted on the MLB and Baseball Prospectus Top 100 lists in 2018 at #90 and #71 overall, respectively. Baseball America placed him at #41 overall a year later and by 2019 he was considered to be Washington’s top prospect.
After slashing .287/.378/.469 with 45 home runs in four minor league seasons, the 6’2″, 210 lb. righty made his debut on April 26th, 2019 against the Padres. In front of 27,128 people at Nationals Park, Carter Alswinn Kieboom went 1 – 4, taking Craig Stammen to deep center field for the first hit and home run of his major league career. It seemed like a promising start for a budding star in Washington, but the Nats only kept Kieboom up for ten more games in 2019. His .128/.209/.282 line across those games were less than ideal but considering it was across a sample size of only 43 plate appearances, it could be somewhat overlooked. After batting .303/.409/.493 over nearly 500 plate appearance in Triple A Fresno over the rest of the season, there was enough reason to hope his initial callup was only a blip on the radar.
Heading into the 2020 season though, card collectors still seemed to be taking a cautious approach towards Kieboom. The ten sales of his first Bowman Chrome autograph card before the season averaged just under $45 despite the twenty-three year old being listed as Baseball Prospectus’s #11 overall prospect. Once the season began, that caution proved to be well warranted. Although he improved upon his first 11 games, it wasn’t by much. Over 122 plate appearances in 2020 the first rounder struggled to stay above the Mendoza line and only slugged .212. The less than impressive results resulted in a 36.9% decline in his card value, averaging $28.36 in the ten most recent sales.
After exhausting his rookie eligibility during the 2020 season, the 2021 season will be pivotal for Kieboom and his collectors. Nats fans would undoubtedly be happy simply to see Kieboom be an average player, although it will probably take much more than that for collectors to regain any lost value. It would be difficult to offload an average player that began his MLB career with a .181 batting average. However, there is still reason to hope things can come together for the Georgia native in 2021. Despite his poor start, Kieboom has still only had 165 plate appearances in 44 games at the top level. He has proved that he does have power and can get on base on the minor league level. 2021 will also be his twenty-three year old season so there is still time before he reaches his peak. Those reasons alone are enough not to write Kieboom off completely just yet but he will need to take a large leap forward in order to stay relevant in the collecting community.