Ryu scratched Friday with lingering back stiffness

DENVER -- Hyun-Jin Ryu has been scratched from his Friday night start in Cincinnati with a stiff back and replaced by Chris Capuano, Dodgers manager Don Mattingly confirmed on Wednesday.

"I'm not really concerned, but we're being a little cautious," Mattingly said of Ryu, who felt tightness when he left his last start Friday night against the Padres after throwing six scoreless innings. "He feels it when he gets to a certain point twisting."

Zack Greinke and Clayton Kershaw will still start Saturday and Sunday, with Ricky Nolasco Monday night against the D-backs. Mattingly said the soonest Ryu would return to the six-man rotation would be Tuesday night.

Ryu said he did not suffer the injury on an awkward slide home while scoring Friday night and he downplayed its severity.

"It could have been from anything," Mattingly said. "He felt it when he came out and the day after his start. Yesterday, he threw and we didn't like the answers we were getting."

Ryu is 13-5 with a 3.02 ERA in his first Major League season and a solid contender for the National League Rookie of the Year Award.