The Rangers released the 41-year-old Ramirez from his Triple-A contract with Round Rock on Tuesday so he can explore other options.
Ramirez played in 30 games for Round Rock, batting .259 with three home runs and 13 RBIs.
"Based on our evaluation, there was not a spot on the club for Manny at this time," Rangers general manager Jon Daniels said.
Ramirez hit three homers in his first eight games with Round Rock but hasn't homered since, as scouts reported that his bat speed has slowed down considerably.
But Ramirez told ESPNdeportes.com that he has no plans to retire.
"I won't retire, I'm going to Miami to continue my training," Ramirez told ESPNdeportes.com on Wednesday. "I will continue waiting for a call from a MLB team ... but anyway, the training will help me to be prepared for the winter season in the Dominican Republic."
A 12-time All-Star, Ramirez is a .312 career hitter and is 14th on the career home runs list with 555. He started out this season playing in Taiwan, where he hit .352 with eight homers and 43 RBIs.
Ramirez was suspended for 50 games in 2009 while with the Los Angeles Dodgers after testing positive for a banned drug. He retired in April 2011 instead of serving a 100-game ban for a second positive test while with Tampa Bay, but later agreed to a reduced 50-game suspension and played in the minors for Oakland in 2012. He won two World Series with Boston.
Todd Wills covers the Texas Rangers for ESPNDallas.com. Information from The Associated Press was used in this report.