The Red Sox announced Sandoval's release on Wednesday.
The move comes five days after the Red Sox designated Sandoval for assignment, giving them up to 10 days to find a trade partner for the struggling third baseman.
It seemed unlikely another team would take a chance on Sandoval given his contract.
Jon Morosi of MLB Network noted the $49.5 million remaining on Sandoval's deal is the second highest total amount of dead money on a contract in MLB history, trailing only the $63 million the Los Angeles Angels gave the Texas Rangers to take Josh Hamilton off their hands.
Sandoval signed a five-year deal with the Red Sox prior to the 2014 season. The two-time All-Star hit .237/.286/.360 in 161 games over three seasons with the team.