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The first hiccup of Stephen Strasburg's much-hyped major league career came during a pregame warmup session on the home bullpen mound at Nationals Park.

After about a half-dozen tosses, Strasburg was approached by Washington pitching coach Steve McCatty, who asked a simple question.

"I just said, 'Well, how're you feeling?' He said, 'I feel stiff. My shoulder's stiff,'" McCatty recalled hours later Tuesday night.

"I said, 'How bad?' He said, 'It's just stiff, but I can get loose.' I said, 'Uh, no.' And that was it," McCatty continued.

McCatty immediately relayed that exchange to Nationals general manager Mike Rizzo, who wasted no time in declaring that Strasburg would be scratched from what was supposed to be his 10th start in the majors.

"Stephen was having trouble getting loose in the bullpen, and so I pulled the plug on it," said Rizzo, adding that he considered it a "precautionary move."

Instead of facing the Atlanta Braves, Strasburg was checked by a team doctor and sent for an MRI and X-ray. Rizzo said none of the tests showed structural problems, and that Strasburg was diagnosed with inflammation in his rather valuable right shoulder.

"No cuff damage. No labral damage," Rizzo said, "so that's good news."

Rizzo said Strasburg, who turned 22 on July 20, is day to day. The team is not certain when the righty will pitch next.

"We're still not sure where he's at," the GM said.

In nine starts for Washington, Strasburg is 5-2 with a 2.32 ERA, 75 strikeouts and 15 walks in 54 1-3 innings. He has won his past three starts.

"For him not to pitch was a little disappointing, but I applaud what the Nationals did, because that's their franchise for the next 15 years, and if he wakes up with a hangnail, I'm pulling him out," Braves third baseman Chipper Jones said. "I want to protect my investment, protect that arm for the next 20 years. Because as he goes, they're going to go."

Strasburg's teammates were a little worried when they learned he was not going to play.

"It lets a little air out of your chest," outfielder Nyjer Morgan said.

The Nationals have been quite careful in the way they have brought along Strasburg since choosing him with the No. 1 overall pick in the June 2009 amateur draft, then giving him a record $15.1 million contract right before the August 2009 deadline for getting deals done.

Even though Strasburg was dominant at times during spring training, he was moved to minor league camp in Florida, then began the season at Double-A Harrisburg. The righty was promoted to Triple-A Syracuse in early May, before making his highly anticipated major league debut June 8 — and, somehow, surpassing expectations by striking out 14 batters in a 5-2 victory over the Pittsburgh Pirates.

He left that game after seven innings, part of a pattern of being eased into the rigors of the major leagues. The Nationals have said they would end Strasburg's season when he reaches 160 innings, even if that cap were to come in late August or early September.

So far in 2010, he's thrown 109 2-3 innings total, including in the minors, which essentially matches his count in his final college season at San Diego State: 109 innings.

"We're going to use common sense and be cautious like we have," Rizzo said. "This is a workload that he's never seen before."

There were scattered boos from the announced sellout crowd of more than 40,000 when the news that 39-year-old journeyman reliever Miguel Batista would be pitching for Washington on Tuesday was delivered via the loudspeakers to fans — many of whom surely purchased tickets precisely in order to watch Strasburg throw his 100 mph fastballs and hitter-confounding breaking balls.

There were more and louder boos before the third inning, when a picture of Strasburg was put on the scoreboard, alongside a written explanation of why he was sitting out.

Batista, who wound up pitching five scoreless innings in Washington's 3-0 victory, took the jeers in stride.

"Imagine," he said, "if you go there to see Miss Universe — and you end up having Miss Iowa."