Cleveland won't have a chance to receive draft-pick compensation for any of the aforementioned players if they depart via free agency.
From 2016-17, Brantley only played in 101 combined games because of ankle and shoulder injuries. The 31-year-old outfielder recovered to hit .309/.364/.468 with 17 home runs, 36 doubles, and 76 RBIs across 143 games in 2018.
Miller, once considered one of baseball's most dominant relievers, struggled to stay healthy last season, making 37 appearances and posting his highest ERA (4.24) since 2011.
The 29-year-old Allen also had a rough campaign, going 4-6 with a 4.70 ERA and 1.36 WHIP across 67 innings, which included 27 saves.
Cleveland isn't expected to have a lot of money to work with during the offseason, which could have factored into its decisions. The club has $50 million committed to Edwin Encarnacion, Corey Kluber, and Jason Kipnis, according to Spotrac.