Nats' Michael Morse out for 6 weeks

Published Apr. 12, 2012 1:00 a.m. ET

Nationals cleanup hitter Michael Morse will be shut down for about six weeks after aggravating the injured back muscle that already landed the left fielder on the disabled list.

Washington general manager Mike Rizzo says Thursday that surgery is not an option and Morse just will need to rest before resuming rehabilitation. Rizzo won't say how long he expects it to take before Morse is able to play for the Nationals.

Rizzo also says Morse's setback will not affect top prospect Bryce Harper's timetable for making it to the majors. The 19-year-old outfielder is at Triple-A Syracuse.

The GM expects closer Drew Storen to pitch this season but wouldn't be more specific. Storen had surgery Wednesday to remove a bone chip from his pitching elbow.