Kieboom went 1-for-2 with a solo home run in Saturday's Grapefruit League game against the Marlins.
He nearly had a second jack, too, flying out to the wall in center field in his first at-bat. Kieboom, the Nats' No. 3 fantasy prospect in our rankings, could be looking at a return trip to Double-A Harrisburg to begin 2019 after posting a lackluster .721 OPS in 62 games there last year, but a solid campaign in the high minors would put him in position to compete more seriously for a big-league job next spring.