CINCINNATI (AP) -- With their lineup finally intact, the Reds have a new concern. Left-hander Tony Cingrani is hurt, leaving their rotation in flux.
Cingrani had to leave in the fourth inning because of a strained lower back, and the Arizona Diamondbacks rode Paul Goldschmidt's grand slam to a 5-2 victory on Tuesday night.
Cincinnati lost for only the fourth time in its last 14 games. The bigger concern is Cingrani (6-3), who has been filling in while Johnny Cueto tries to come back from soreness behind his pitching shoulder that has sidelined him most of the season.
"We certainly can't afford any more injuries to our starting staff, especially going down the stretch," manager Dusty Baker said. "He was throwing the ball so well."
Cingrani retired the first 10 batters before Martin Prado hit his 12th homer. One out later, Aaron Hill doubled off the wall in left-center, extending his hitting streak to 13 games. That's when Cingrani informed Baker and a trainer that his back has been bothering him lately and was getting worse.
"It finally bothered me enough that it was noticeable," Cingrani said. "I felt it before. It came on gradually. It hasn't been this bad."
He hadn't told Baker or the coaches about his back, trying to pitch through the problem.
"He said it's been bothering him on and off for the last couple of weeks," Baker said. "He didn't tell me. These young guys want to say in the big leagues and stay in the rotation."
The defending NL Central champions were feeling good about getting their starting lineup back to full strength with Ryan Ludwick's return last week from a shoulder injury that had sidelined him since opening day. Now, the rotation is a question as they try to overtake Pittsburgh and St. Louis.
The game got away in the eighth inning, when Goldschmidt set a Diamondbacks record with his third grand slam of the season and became the first NL player to drive in 100 runs.
Goldschmidt connected in the eighth inning off J.J. Hoover, ending the reliever's streak of 23 scoreless appearances. His 31st homer tied him with Pittsburgh's Pedro Alvarez for the NL lead. All of his career grand slams have come this season.