Santana's contract is for $14 million and Morrison's for $8 million. In announcing the expected decision Tuesday, the team will pay each player a $1 million buyout to make him a free agent.
Morrison, 31, batted .186 with 15 home runs in 95 games in his only season with Minnesota before needing surgery on his left hip.
Santana, 35, underwent surgery on his right middle finger two weeks before spring training and didn't debut with the Twins until July 25. With an 8.03 ERA in 24⅔ innings over five starts, the right-hander was shut down again. Over the 2016 and 2017 seasons, Santana went 23-19 in 63 starts with a 3.32 ERA, seven complete games and four shutouts.