BALTIMORE -- In the midst of what was shaping up to be a dominant performance, Red Sox lefty Eduardo Rodriguez left Tuesday's 5-3 win against the Orioles with tightness in his left hamstring in the fifth inning.
Rodriguez held the Orioles hitless through the first four innings, striking out seven while allowing just two walks. He exited after throwing two balls to Steve Pearce to start the fifth.
The Red Sox are hopeful they caught the injury early enough that it won't be an issue going forward.
"I think we got this early," said Red Sox manager John Farrell. "He felt a little bit of hamstring tightness come on towards the last hitter of the fourth inning. We checked him in between innings. There was no reduction of strength or range of motion, but it was clear the first two pitches he threw to start the fifth [that] he was not right.
"He was definitely favoring it, so we got him out of the game at the time. He feels a little bit looser postgame. We'll have a better read on this tomorrow."
It was tough for Rodriguez to come out at a time he felt his stuff might have been the best of his young career.
"From last year to this year, that was the first time I felt like that," Rodriguez said. "Every pitch was right where I wanted -- the fastball, changeup, slider, two-seam. Everything was right where I wanted."
Rodriguez spent the first two months of the season on the disabled list due to a right knee injury he suffered early in Spring Training.
After struggling mightily and then being optioned to Triple-A Pawtucket, Rodriguez has thrived since his recall after the All-Star break, posting a 2.51 ERA.
"He's thrown the ball like he has the last few starts," said Farrell. "He's relaxed, he's free. He had such good life to that swing and miss fastball through the zone. He elevated at the appropriate times. He threw enough secondary pitches to keep guys off stride. He had a very good fastball tonight."
Rodriguez hopes the hamstring injury doesn't derail his recent momentum.
"I felt it on one pitch before the strikeout to [Mark] Trumbo," said Rodriguez. "When I threw the pitch, I felt something get tight in there. When I came out for the fifth, I was feeling like it was getting worse, so I didn't want to do something to something inside of there. I feel like we made the right decision before it got worse."
Ian Browne has covered the Red Sox for MLB.com since 2002. Follow him on Twitter @IanMBrowne and Facebook. This story was not subject to the approval of Major League Baseball or its clubs.