Washington, DC -- (Sports Network) - The Washington Nationals placed right fielder Austin Kearns on the 15-day disabled list Thursday with a right elbow injury.

Kearns is scheduled to undergo arthroscopic surgery Friday to remove loose bodies from the elbow and is expected to miss three to four weeks.

The 28-year-old is in the midst of a season-long slump, hitting just .187 with three home runs and 16 runs batted in through 42 games. Kearns is now the fourth member of Washington's opening night lineup currently on the disabled list, joining first baseman Nick Johnson, catcher Paul Lo Duca and second baseman Ronnie Belliard.