Kieboom is out of the lineup for Sunday's game against the Marlins, Mark Zuckerman of MASNSports.com reports.
Kieboom will cede third base to Ildemaro Vargas for the series finale after starting in each of the past five games. Since receiving a call-up from Triple-A Rochester on Aug. 20, Kieboom has gotten on base at a .275 clip in 10 games, but he's showcased some good power (three home runs and a double). The Nationals will likely give Kieboom an extended look as their everyday third baseman down the stretch.