The 36-year-old former all-star was placed on the 15-day disabled list April 27 after complaining about pain in the shoulder and went to the DL for the first time in his 14-year career.
"All of the doctors agree that it just needs rest and to get the shoulder strong," Posada said after the last of four visits to doctors.
He also has seen Reds team physician Dr. Timothy Kremchek, noted sports surgeon Dr. James Andrews in Birmingham, Ala., and Mets medical director Dr. David Altchek.
The doctors concurred that the shoulder contains no structural damage.
To date this season, Posada is batting .302 with one home run and 11 RBI in 63 at-bats.