"I don't know yet. I don't want to speculate," said Norris, acquired from Atlanta when ace Clayton Kershaw went down with a herniated disk that has him shelved indefinitely. "My goal is to be back in five or six days. I hope to get a healthy side session in and get this out of my head."
Norris said he was able to pitch through a previous lat strain years ago. This time -- which he said happened either on a pickoff throw after walking leadoff hitter Jean Segura, or a pitch to Michael Bourn when his landing foot slid -- he was unable to get the area behind his right shoulder blade loose.
"I think we made the right choice," he said of coming out. "It's just really uncomfortable -- achy, dead pain. I hope with a couple nights of sleep I can throw."
Norris grabbed his back seven pitches into the game, bringing Roberts and assistant trainer Nate Lucero to the mound. After a couple practice throws, Norris was allowed to continue.
But after Norris retired Bourn on a popout, Roberts and Lucero again came to the mound and this time took Norris back to the dugout with them, as Ross Stripling took over pitching duties, with the bullpen finishing the final 8 2/3 innings.
Norris was acquired June 30 from Atlanta as an emergency replacement for Kershaw. Norris' injury comes one day before the non-waiver Trade Deadline, with the Dodgers having already been linked to possible deals for starting pitchers Chris Sale, Chris Archer and Matt Moore, among others.
The club's starting rotation has been beset by injuries since last year, when Hyun-Jin Ryu (shoulder) and Brandon McCarthy (elbow) had season-ending surgeries.
While McCarthy has returned to the rotation, Ryu pitched one game on July 7, then returned to the DL with an elbow injury. Brett Anderson is on the comeback trail from spring back surgery, but Alex Wood is out after elbow surgery.
The Dodgers have only four starters listed in their rotation: Norris, McCarthy, Scott Kazmir and Kenta Maeda.
Ken Gurnick has covered the Dodgers for MLB.com since 2001.