Kearns will have elbow surgery on Friday and is expected to be out three to four weeks. Dr. Tim Kremchek, the Reds' physician, will perform the surgery. Kearns hurt the elbow on Saturday during batting practice and hasn't played since.
"Dr. Kremchek felt that Austin should not wait. It's not going to get any better," general manager Jim Bowden said. "We hope to get Austin and Nick [Johnson] back by July 1."
Kearns, 28, is currently hitting .187 (28-for-150) with three home runs and 16 RBIs in 42 games.
The Nationals will make a corresponding roster move prior to Friday's game against the Brewers. The decision they have to make will be a tough one. Outfielders Ryan Langerhans, Roger Bernadina and Mike Daniel are all candidates to be promoted to the big leagues.
Langerhans is hitting .312 with three home runs and 24 RBIs for Triple-A Columbus, but he is dealing with hamstring issues.
Bernadina and Daniel are with Double-A Harrisburg. Both players are hitting over .300. However, the Nationals would like to have them develop some more in the Minor Leagues.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.