"It's just one of those things I've actually felt before. It's been in and out throughout the course of my career," said Lewis, who picked up his first loss of the season after getting out to a career-best 6-0 start. "Nothing that's really got as tight as it did tonight. So before I started to feel any type of pain, I said something."
The 36-year-old righty began feeling the tightness after the first couple of sliders he threw in the first inning, an inning that was rough for him, as he allowed a three-run shot to Reds cleanup hitter Jay Bruce.
He had retired 11 straight going into the fifth inning before allowing three more runs, on a two-run triple by Zack Cozart and Billy Hamilton's sacrifice fly.
"It just [stinks], because even though I was giving up runs, the pitch count was down, and I could have saved the bullpen for at least three more innings," he said.
"The two-strike counts which he's been good at all season -- he seemed to get hurt in those situations," manager Jeff Banister said. "Typically, that comes down to execution."
Banister hadn't gotten to talk to Lewis in depth prior to his postgame news conference.
"Obviously, we got him out when he communicated to us where he was at -- precautionary," Banister said. "I'll definitely talk to him here in just a little bit, and we'll have a little more communication on that."
Lewis is not concerned "at all" about the tightness, saying that he's never missed time in his career with this type of injury.
"I feel like if it's anything, it's going to be a Charley horse, it's going to be sore," he said. "The muscle was [cramping] in and out, kind of like a back issue or something where you just work out and let the muscles rest and get it back right."
Pitching in relief of Lewis, left-hander Cesar Ramos didn't find much more success. He allowed two runs on five hits through two innings after throwing 2 2/3 scoreless innings against the Cardinals on Saturday.
"Just falling behind," Ramos said of the difference between his last two outings. "It's frustrating, but I'll go back out there and get back on track."
Fellow lefty Alex Claudio threw two scoreless innings to close out the game, allowing just one hit. The Rangers saw their season-high seven-game winning streak snapped and their franchise record of 10 straight series wins came to an end.
"Still felt like we had good energy, guys are playing hard all the way through the end," Banister said. "We're not going to overanalyze this game."