Kendrick has been on the disabled list since Aug. 9 with a strained hamstring. The Dodgers were hoping that Kendrick could make a rehab appearance in the Minors on Sunday, but that plan is in doubt as the 30-year-old continues to rehabilitate the injury.
"We were kind of hoping he can play baseball by Sunday but that doesn't look like it's going to happen," Mattingly said. "I don't worry about the rehab nearly as much as I would in the beginning of the season when guys don't have their timing and haven't been playing a lot of baseball."
Even with the Minor League season ending in early September, Mattingly said Kendrick could get live at-bats at the Dodgers' extended spring training facility in Arizona.
Kendrick is hitting .296 this season with nine home runs and 49 RBIs. The Dodgers acquired Chase Utley to fill the void at second base, and the veteran is hitting .190 in six games with Los Angeles.
Steve Bourbon is an associate reporter for MLB.com.