Cain looks to continue his recent dominance of the Dodgers and help the Giants extend their lead in the NL West on Friday night.
San Francisco (55-43) leads Los Angeles (53-47) by three games in the division, and has won four of six meetings this season.
The Giants dominated the most recent series, outscoring the Dodgers 13-0 in a three-game sweep from June 25-27. It was the first time San Francisco blanked Los Angeles in three straight games.
Duplicating that feat might be tough with the Dodgers having added Ramirez to go with a healthy Kemp.
Ramirez is 3 for 6 with a triple, an RBI, three walks and a stolen base in two games after the Dodgers acquired him in a four-player deal with Miami. However, they've lost both of those contests and their losing streak reached three with a 7-4 defeat at St. Louis on Thursday.
''It seems like the momentum we had kind of shifted the other way on us,'' catcher Matt Treanor said. ''I think we're looking forward to leaving town and get fired up for the Giants.''
Kemp, batting .339 with 14 homers and 34 RBIs, missed the last series at San Francisco with a hamstring injury. He was 2 for 16 with seven strikeouts in the four-game set against the Cardinals.
"We're still in a good spot," Kemp told the team's official website. "We've got Hanley now and whoever else may come. We're right there with a big series coming up. We win those games and we're right back in this thing."
Avoiding a fourth straight loss won't be easy with the Giants scheduled to give the ball to Cain (11-3, 2.70 ERA), who is 3-0 with a 1.80 ERA in his last five starts against the Dodgers with San Francisco winning all of them.
The right-hander has held Ramirez to 2 for 12 with five strikeouts over the last three years, while limiting Kemp to 4 hits in the last 19 at-bats.
Cain, however, hasn't been particularly sharp in his last four starts, going 1-1 with a 4.55 ERA while yielding seven homers.
He gave up a season high-tying five runs and three homers while connecting for one of his own in eight innings of Saturday's 6-5, 10-inning win at Philadelphia.
The Giants' six-game home winning streak ended with a 6-3 loss to San Diego on Wednesday. Even with an 0-for-3 performance in that defeat, Melky Cabrera is hitting .390 with 11 runs in the past 10 games overall. He's 8 for 23 against Los Angeles this year.
Dodgers manager Don Mattingly hasn't announced who will counter Cain, but one option is to recall Stephen Fife (0-0, 1.50) from Triple-A Albuquerque. Fife, though, can't be brought back unless there's an injury since he was sent to the minors less than 10 days ago.
That opportunity may present itself since Scott Elbert's sore left shoulder may lead to a stint on the disabled list.
Fife was impressive in his major league debut July 17, allowing one run and four hits in six innings before leaving without a decision in a 3-2 loss to Philadelphia.
The right-hander followed that up with another strong performance for Albuquerque on Sunday, striking out 12 while yielding one run and four hits in seven innings of a victory.
Overall, Fife is 8-5 with a 4.31 ERA in 19 minor league starts.