The 33-year-old, who last played for the Cleveland Indians, is drawing plenty of interest despite coming off his worst season in seven years. The New York Yankees, Mets, and St. Louis Cardinals are also in the race for the two-time All-Star.
Miller posted a 4.24 ERA in 37 appearances while battling injuries in 2018. However, he still maintained a high strikeout rate (11.9 SO/9) and kept the ball in the park (0.8 HR/9).
Before last season, Miller was one of the most dominant relievers in the game.
The Phillies' bullpen finished 11th in team ERA and opposing team batting average in the NL last season.