ST. PETERSBURG -- Brad Miller became the casualty when Tampa Bay made its corresponding move to make room for first baseman Jake Bauers, whom the Rays recalled from Triple-A Durham.
"Look, Brad's done a lot of good things in his time here," Rays manager Kevin Cash said. "He's just an unbelievable teammate. ... We're getting a good one [in Bauers], but we're also losing a good one in saying that. But in fairness to Brad and his career, he's a Major League player.
"We're going to do everything we can to find a spot for him to continue being that. I didn't think it was fair to him for what he's done to come and sit on the bench, neither did the front office. This was the move we felt was necessary."
When a player is designated for assignment -- often abbreviated "DFA" -- that player is immediately removed from his club's 40-man roster, and 25-man roster if he was on that as well. Within seven days of the transaction (it was previously 10 days), the player must either be traded, released or placed on irrevocable outright waivers.
"To this point in the season, what [Miller has] done offensively, it's been OK," Rays GM Erik Neander said. "I think he believes he can do better. I think we believe he can do better. But really, at the end of the day we wanted to prioritize Jake, create an opportunity for him. And that's what really drove this decision."
Miller enjoyed a productive game Wednesday, his final game with the Rays, going 3-for-4 with a double in Tampa Bay's 11-2 loss to the Nationals. He now cedes his role to Bauers, the Rays' No. 5 prospect according to MLB Pipeline. On the year, Miller is batting .256/.322/.429 with five homers and 21 RBIs through 48 games.
The 28-year-old Miller was in his third season with Tampa Bay. The Rays acquired him along with Danny Farquhar and Logan Morrison in a deal with the Mariners on Nov. 5, 2015, in exchange for Nate Karns, Boog Powell and Charles Riefenhauser. 
In three seasons with the Rays, Miller has hit .231 with 44 home runs and 142 RBIs in 310 games.
Miller is making $4.5 million this season and has struggled since 2016, his first season with the team when he hit 30 home runs.