"I promise you that," Mattingly said.
He announced that rookie Stephen Fife will start Sunday, and the Dodgers will try a four-man rotation as days off allow. Fife has three Major League starts and a 2.16 ERA.
Kershaw pitched Tuesday night in Arizona, a start delayed two days because of the hip inflammation that caused his late scratch Sunday in San Francisco. Against the D-backs, Kershaw was typically stingy, allowing only one unearned run on three hits over seven innings while drawing a 1-0 loss.
In the aftermath, his hip was inflamed enough that he scrubbed a scheduled Thursday bullpen session. On Friday, he tried to play catch with trainer Sue Falsone watching but shut down after a couple tosses and retreated to the trainer's room. He missed batting practice for the starting pitchers and didn't shag in the outfield.
Last week, Kershaw threw his bullpen session on the Thursday off-day but alerted the club on Friday when he felt the pain. He underwent a contrast MRI and received a cortisone shot on Saturday and said he felt well enough to pitch on Sunday, but management decided to give him two extra days.
Mattingly said Kershaw would not have a second cortisone shot "as a masking agent."
Unlike last week, Mattingly said that Kershaw didn't argue the decision to scratch Sunday. Kershaw played catch with teammates Saturday, but mostly without moving his lower body.
"There was no fight as far as him wanting to try and pitch," said Mattingly. "He knows he can't pitch like this."
Kershaw would not speak with the media. The club withheld comment about chances for labral surgery -- which is arthroscopic but not minor, requiring a rehab of three to five months -- until Tuesday's second opinion.
But Mattingly said he's prepared to finish the season without the reigning National League Cy Young winner.
"Really right now you don't have time to brace yourself and it's really not a good thought," he said. "It's almost like any other time when you don't want to think about having to go through it without Kersh because you can always count on him saving your 'pen. He's going seven [innings] usually and it's pretty much the 'pen getting the day off and you know you are going to be in the game with a pretty good chance of winning. Other than all those factors, you just move on and you've got to get it done."
The continued bad news on Kershaw comes in the wake of season-ending injuries to fellow starters Chad Billingsley and Ted Lilly.