But the right-hander didn't let it bother him Tuesday night, as he tossed another complete inning following the impact and earned the win during Cincinnati's 5-2 victory over the Tigers.
"It's going to be pretty big," Lorenzen said of the impending bruise on his leg. "It's going to be tough to get some running in tomorrow, but we'll make it through. We'll be all right."
Lorenzen threw only one clean inning on Tuesday, but he limited the damage to two runs (one earned) over six frames. It was a much-needed rebound outing for the rookie after he allowed six runs (five earned) on Thursday against the Cubs.
"I thought that the way he went about his business today, he just showed that he was willing to go out there and attack," said Reds manager Bryan Price. "We played some nice defense behind him, and he made the pitches he needed to make."
The Tigers were the ones attacking early. Center fielder Anthony Gose doubled on the second pitch Lorenzen threw with a soft fly ball that dropped into shallow left field. Two batters later, Miguel Cabrera singled to right field for a 1-0 Tigers lead.
But Lorenzen eluded further trouble by inducing a Cespedes flyout and then snaring a J.D. Martinez line drive. The right-hander was by no means perfect afterward -- he allowed four more hits and walked three -- but he kept the Tigers scoreless until an error-aided fifth-inning rally.
After James McCann led off the fifth with a single and was sacrificed to second, left fielder Ivan De Jesus misplayed a line drive, giving Detroit two runners in scoring position with one out. Lorenzen retired Ian Kinsler on a flyout and intentionally walked Cabrera, but Cespedes followed with a scorching line drive off the pitcher's shin and into foul territory, driving home McCann.
Anthony Gose was thrown out trying to score from second, ending the inning, and Lorenzen induced a double play in the sixth to finish his night at 100 pitches.
"I just had peace and confidence that I was able to make some pitches and try and get out of it," Lorenzen said.
The Reds reclaimed the lead for good in the seventh, and the club's bullpen combined for three scoreless innings to seal the win. Tuesday's result ended Cincinnati's six-game road trip on a positive, and, in Price's opinion, may have helped build Lorenzen's confidence for managing difficult situations.
"That's the only way you're going to be successful at this level, is feeling like you belong and knowing that your stuff plays up to this level and just trusting it," Lorenzen said. "I work too hard to be scared when I face a lineup like this. I just have to put the faith in the work that I've put into it."
Alejandro Zúñiga is an associate reporter for MLB.com. Follow him on Twitter @ByAZuniga.