Manager Davey Johnson made the announcement Saturday morning with the Nationals holding the best record in the majors. He said the media attention surrounding the innings limit for the 24-year-old right-hander was affecting the pitcher.
"I just told Stephen that his year is over. He's had a great year. I know what he's growing through," Johnson said. "The media hype on this thing has been unbelievable. I feel it's as hard for him as it would be anybody to get mentally, totally committed in the ballgame. And he's reached his innings limit. So we can get past this and talk about other things for a change."
Johnson said Strasburg was "emotional" about the decision to end his season immediately. A day earlier, the overall No. 1 pick from the 2009 draft matched a career low by lasting only three innings against Miami.
"He's one heck of a pitcher and he's a heck of a competitor," Johnson said. "I know he's been struggling with it for weeks. I know he doesn't sleep good thinking about it."
Strasburg went 15-6 with a 3.16 ERA in his first full season following elbow-ligament replacement surgery on Sept. 3, 2010. He struck out 197 in 159 1-3 innings.
The Nationals had said Wednesday's start at the New York Mets likely would be his final appearance of the season. John Lannan will make that start and remain in the starting rotation.
Johnson said the decision was his, and pitching coach Steve McCatty and general manager Mike Rizzo were in agreement.
"My job is to do what's best for the player. And this is what's best," Johnson said. "If you're not there 100 per cent mentally — he's a gifted athlete, his velocity can still be there — but I don't see the crispness. I don't see the ball jumping out of his hand. I'm a firm believer that this game's 90 to 95 per cent mental and he's only human. I don't know how anybody can be totally mentally concentrating on the job at hand with the media hype to this thing and I think we'd be risking more by sending him out."
Strasburg allowed five runs in the Nationals' 9-7, 10-inning loss to the Marlins on Friday night.
"This is a plan we put in place February 1st, we've been true to the plan and we haven't wavered from it one bit," Rizzo said. "This is just the culmination of that plan. I believe in my heart that it's the right thing to do for the player and the right thing to do for the player is the right thing to do for the franchise."
The Nationals had not spelled out exactly how many innings would pitch this season, although there was a lot of speculation that 160 was around the limit.
"He's had a terrific season for us," Rizzo said. "You couldn't ask for anything more coming off his first season off of Tommy John surgery. He's a huge part of where we're at right now."