The last thing the Nationals wanted to deal with this season was an injury to rookie pitcher Stephen Strasburg. They built an entire innings plan on limiting the risk to their 21-year-old star. But this is the nature of a starting pitcher. Injuries crop up out of nowhere. Strasburg threw a clean bullpen session earlier this week, according to Nats general manager Mike Rizzo, and played catch on Monday in preparation for tonight’s start against the Atlanta Braves.

But as Strasburg warmed up in the bullpen just minutes before first pitch he was having trouble “getting loose” as Rizzo vaguely termed it. Pitching coach Steve McCatty reported that news to trainer Lee Kuntz, who in turn notified Rizzo. The decision was made right then – Strasburg would be scratched. The big crowd on hand to watch the rookie’s 10th big-league start booed when it realized Miguel Batista had taken the mound. But the Nats just aren’t going to mess around with their prized youngster.

“Those are decisions I get paid to make,” Rizzo said. “Like I said, we’re going to err on the side of caution. I make the decisions and take the heat for it.”

Plenty of questions remain, though. Was Strasburg hiding any kind of physical problem? That seems unlikely considering his velocity has stayed about the same in recent outings as when he arrived in the majors last month. Rizzo said there was no shooting pain in the shoulder or elbow. Strasburg just couldn’t get loose. As a first-year pro this is by far the largest - and most taxing - workload of his career. He is up to 109 2/3 innings total – 55 1/3 in the minors and 54 1/3 with the Nats. Then again, an MRI and x-rays for a pitcher who couldn’t “get loose” seems a bit excessive. But the investment the organization has made in Strasburg is so great you almost can’t blame it.

“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 and we’re going to take it from there.”

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