The Rockies immediately designated Harang for assignment, meaning they are likely looking to trade him.
The move allows the Dodgers to unclog a logjam of starting pitchers and to acquire a veteran backup for catcher A.J. Ellis. Hernandez, 36, is a former All-Star who the Rockies designated for assignment near the end of spring training. He and Harang, 34, were teammates on the Oakland A's in 2002 and 2003.
According to reports, the Dodgers are sending Colorado $4.25 million. Harang is earning $7 million with a $2 million buyout for next season. Hernandez is earning $3.2 million.
Harang went 10-10 with a 3.61 ERA in 31 starts for the Dodgers last year, but was shifted to the bullpen after the Dodgers acquired pitchers Zack Greinke and Hyun-Jin Ryu in the offseason. Harang met with manager Don Mattingly Friday to discuss a role that appeared to be minimal. He had not appeared in a game this season.
"Ramon gives us invaluable veteran experience and additional leadership at the catching position," Dodgers general manager Ned Colletti said in a statement. "He's worked with great pitching staffs in the past and we feel he will provide solid contributions to our pitchers and be a great resource for A.J."