Washington, DC (Sports Network) - The Washington Nationals have decided to put rookie phenom Stephen Strasburg on the 15-day disabled list with inflammation in his right shoulder.

Strasburg is expected to rest for the next 3-to-4 days and have the shoulder re-evaluated. However, the Washington Post reported that manager Jim Riggleman said Strasburg would be shut down for 10 days, citing a radio interview given Thursday morning.

The 22-year-old was scratched from his scheduled outing on Tuesday night versus Atlanta after having trouble getting loose in the bullpen. He will miss at least his next start, which was scheduled for Sunday against the Philadelphia Phillies. The move is retroactive to July 22.

Strasburg was off to an electric start for the Nationals, posting a 2.32 earned run average and 5-2 record. In 54 1/3 innings, he has 75 strikeouts compared with only 15 walks. He has pitched 109 2/3 innings overall this season after having thrown 109 total innings for San Diego State all of 2009.

"I was feeling tight a little bit, wanted to get out there and see if it would loosen up," Strasburg said Wednesday about missing his start. "It's just one of those days where it was tighter than normal. I'm just at a point right now in the season now where I'm going into uncharted territory. I have to be smart right now and look at the big picture."

Strasburg also said his condition has improved since Tuesday.

"I feel a lot better. My range of motion, after going through some stretching and everything is starting to come back to me," Strasburg said. "I made some big strides today. I'm not going jump the gun, just going to take it day-by- day."

Washington's starter for Thursday against the Braves, Scott Olsen, was reinstated from the 15-day DL in a corresponding move. He had been suffering from left shoulder tightness and entered the contest with a 2-2 record and 3.77 ERA in eight starts with the Nationals this season.

07/29 16:08:59 ET