"Don't hold me to that, but I think he's going to DH tomorrow," Mattingly said after the Dodgers beat the Cubs, 4-0, on Wednesday afternoon.
Kemp ran sprints and made curves in the outfield at Dodger Stadium on Wednesday morning after running hard on the bases on Tuesday for the first time since he injured his ankle in an awkward slide at home plate July 21 in Washington.
"I think he passed all the tests," Mattingly said. "It seems like it's taken a while, but we're there. We've kind of survived, and hopefully we get Matt sharp and it gives us more options with our players."
Rancho Cucamonga's season ends on Monday, so Kemp would have five opportunities to play rehab games. The former All-Star has 37 at-bats in the Major Leagues since June 25, and has said he's unsure of how many rehab games he needs.
"I think the timetable puts a little bit of a time crunch on it," Mattingly said. "But along that same line, it doesn't mean we can make it happen faster. We have to make sure he's ready, so he can go out and play full speed. We have to make sure that Matt is right before he goes out there."