CINCINNATI — And just like that, Stephen Strasburg was gone, removed from Friday night’s game in Cincinnati after five batters. A sore left trapezius muscle was the culprit this time, tightness in the upper left of his back and in his neck.

Strasburg said he did not feel the injury before the game, and felt fine in the first inning. He allowed a run on two hits in the first, including a home run to Joey Votto, who hit a 97 mile per hour fastball to the opposite field. But he was hitting 97. He looked okay. But after he walked Reds catcher Brayan Pena on a fastball that stayed too far to his arm side — away from the left-handed Pena — catcher Wilson Ramos headed out to the mound, where he was met by Nationals trainer Lee Kuntz, Manager Matt Williams and pitching coach Steve McCatty. The conversation was quick. Williams signaled for Taylor Jordan. Strasburg departed early again.

“It’s pretty stiff,” Strasburg said after the game. “I don’t know why. It felt fine the first inning, and once I sat down in the second I just felt it tighten up a little bit. I threw some hot stuff on it, and it just progressed. It’s hard for me to turn my head to the left. It was just something where I didn’t feel like I would be able to throw out of the corner of my eyes. Just didn’t want to push it too much.”

The only signs of trouble were pitches left where Strasburg didn’t want them, and an occasional lean of his neck to one side, as if he were trying to stretch it. He said it wasn’t one pitch that alerted him to trouble, but just a gradual tightening between innings. Strasburg and Williams said they will reevaluate the injury when Strasburg reports in the morning. Strasburg left his May 5 start after three innings with lower back trouble, which a chiropractic adjustment alleviated. He has made it past the fourth inning just once in his past five starts.

“We don’t know at this point,” Williams said. “We have to see how it is tomorrow and evaluate. It’s the other side [than it was earlier this month] and we’ll see what he shows up with tomorrow.”

Williams said he noticed something was up in the second inning, that Strasburg “came out of the bullpen good” and the first inning fine. Strasburg said he felt the same way.

The 26-year-old is in the toughest stretch of his career. He has not lasted past the fourth inning in four of his last five starts. He is pitching to a 6.55 ERA in nearly 50 innings, a small sample, but not small enough to write off entirely. All the while, he has maintained velocity, break and bite. The results have not followed. He has battled mechanics and injuries all season. He did not miss a start when he struggled with back pain earlier this month — just started a few days late. The Nationals may opt to place him on the disabled list this time, given the repeated struggles with soreness and unrelenting frustration.

“Yeah (it’s frustrating),” Strasburg said. “I’m trying to go out there and work through it and help this team win. It’s just something I gotta pull through and just ride it out and know that it’s gonna get better eventually.”

Before Friday’s game, Nationals General Manager Mike Rizzo said he believed Strasburg was healthy.

“His stuff is there. He feels good,” Rizzo said. “When his stuff is there and he feels healthy, and he says he feels healthy, and his stuff shows me that he’s healthy, he’s proven he’s one of the top pitchers in the league.”

His stuff was there again Friday, but more trouble popped up. When Strasburg felt back pain earlier this month, he and Williams attributed it to the adjustments in mechanics he made to compensate for the ankle injury he suffered in spring training. No one said as much Friday, but perhaps continued compensation led to this latest tightness. Perhaps it didn’t. Either way, Strasburg’s early departure left Taylor Jordan to try to eat innings. He did, pitching four scoreless innings before faltering in the sixth.

“It’s frustrating for (Strasburg),” Williams said. “What it does for us is it puts us in a position with our bullpen where we don’t want to go. Good thing is, we’ve got a long guy down there, but we have to try to push him through a number of innings. Tonight was a situation where we have to try to get him through the sixth. We can’t just blow our bullpen. We don’t have another off-day for a week. It didn’t work out tonight, but we’ll address Stras tomorrow and see where he’s at. Make a decision then.”