Nationals' Carter Kieboom: Placed on injured list

Kieboom (knee) was placed on the 7-day minor-league injured list Monday, freelance baseball writer Byron Kerr reports.

Kieboom's knee injury has kept him sidelined since June 29, and it's not yet clear when he'll be able to return to action. His placement on the injured list will clear room on the Triple-A roster for Humberto Arteaga, who was outrighted to Triple-A Rochester as part of a corresponding move.