Miami (51-61) dealt Ramirez to Los Angeles (60-52) on July 25 along with left-handed reliever Randy Choate for right-hander Nathan Eovaldi and minor league pitcher Scott McGough. Ramirez has a $15 million salary this year and is owed $15.5 million next year and $16 million in 2013.
The three-time All-Star, who had been with the Marlins since 2006, batted .246 with 48 RBIs in 93 games in 2012 with Miami. He is hitting .226 with 12 RBIs in 14 games with the Dodgers.
"The Marlins will always be part of me," Ramirez told the Dodgers' official website. "They gave me the chance to play in the big leagues, and my family will always live there."
It's unclear what reception he will get in Miami, where the Marlins rank in the bottom half of baseball in attendance despite opening a new stadium.
"I don't know what to expect fan-wise," manager Don Mattingly said. "They are not drawing real well."
Ramirez and Reyes have each won NL batting titles within the last three years, and the Marlins shortstop has finally resembled that player again after a slow start in his first season with Miami.
Reyes, though, went 0 for 4 against All-Star knuckleballer R.A. Dickey in Thursday's 6-1 road loss to the Mets, ending his career-high hitting streak at 26 games. It was the longest run by a reigning batting champion since Joe DiMaggio's record 56-game streak in 1941.
"It's over," Reyes told the Marlins' official website. "I have an opportunity to start a new one tomorrow."
Reyes, playing with a sore right hand, still enters Friday with a .351 average during a 10-game hitting streak at home. He's 3 for 10 against Clayton Kershaw, who starts Friday for the Dodgers.
Kershaw (9-6, 2.88 ERA) has given up one run over 16 innings in winning consecutive starts. That run came over seven frames Saturday in a 3-1 victory over the Cubs, as he struck out seven for the second straight outing.
The left-hander remains among the major league leaders in opponent batting average at .216. He's 2-1 with a 2.30 ERA in four career starts against the Marlins.
Carlos Lee is 4 for 19 against Kershaw but enters this contest on a 14-game hitting streak, batting .420 with 13 RBIs. However, he went 3 for 23 in six games against the Dodgers this year while with Houston.
Los Angeles is one game behind San Francisco for the NL West lead as it begins a 10-game trip after avoiding a three-game sweep by Colorado with a 6-4 victory Wednesday.
The Dodgers haven't enjoyed success against Mark Buehrle (9-10, 3.70), who is 3-1 with a 1.50 ERA in four career starts against them heading into this outing Friday.
The Marlins have dropped the left-hander's last four starts. He is 0-2 with a 7.08 ERA in that span, although he is 6-3 with a 2.69 ERA at home.