Back tightness cuts Strasburg's outing short

WASHINGTON -- Nationals right-hander Stephen Strasburg left Sunday's game against the Marlins after four innings because of back tightness and was replaced by right-hander Doug Fister in a 7-4 victory.

Strasburg allowed four runs on seven hits. In the first inning, he allowed a three-run homer to Justin Bour, and a solo shot to Derek Dietrich three innings later. The Nationals noticed that Strasburg's velocity on his fastball was down, so they decided he was done for the day.

"He had some discomfort in his upper back, so it was a little bit of a recurrence of earlier in the year. The velocity came down today, so we got him out of there," manager Matt Williams said. "He certainly had more pitching to do, but the last thing we want to do is change mechanics. We can't go there."

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Strasburg said he has a "little ball" in his back and doesn't know what it is. He noticed something was wrong in his previous start against the Padres, but normal treatment helped the tightness go away. It's not known if he will make his next start against the Braves.

"Sometimes it gets upset. I tried to battle through it, but the offense came through for me today," Strasburg said. "It's something that is hard to explain. It's not really like a muscular thing. It's like this little ball that is there and it affects everything around it. The biggest thing is to get it calmed down the next couple of days. Hopefully, I'll make the next start."

The last time Strasburg suffered back problems was May 5 against the Marlins. He left that game after three innings and went to a chiropractor later that day and had the problem fixed. Strasburg made it known that he did not have a shoulder issue. He believed changing his mechanics was the reason for the problem.

Strasburg was throwing across his body quite a bit, so the plan was to have better alignment while throwing toward home plate.