"Fausto [Carmona] is our fifth starter," Indians manager Eric Wedge said, confirming what had been expected for several days.
Miller, who had pitched 14 scoreless innings this spring, was one of six players trimmed from the roster Tuesday morning.
Pitchers Jeff Harris and Tony Sipp, outfielder Trevor Crowe and catcher Wyatt Toregas were also re-assigned to the Minor League camp, while right-hander Brian Slocum was optioned to Triple-A Buffalo.
Carmona, 2-1 with a 3.60 ERA in four Grapefruit League starts, did not travel with the team to Progress Energy Park and will start Thursday night against the Detroit Tigers at Joker Marchant Stadium in Lakeland. In 10 innings this spring, the right-hander has given up 10 hits and three walks while striking out five.
The 23-year-old Dominican went 1-10 with a 5.42 ERA in 38 games, including seven starts, for the Indians as a rookie last season. Like a lot of rookies, Carmona was inconsistent. During one stretch between April 30 and July 1, Carmona allowed just three runs and struck out 19 in 18 1/3 innings. On the other hand, opponents batted .374 against the right-hander, including .395 after the break.
Wedge said Carmona's struggles at closer should not overshadow the great job Carmona did as a starter and the "unbelievable" job the youngster did in a setup role for six weeks.
"He's not the first one to have that happen," Wedge said. "It's not about getting knocked down, it's about getting back up and he got right back up. He didn't make any excuses, he went right back after it. He has a bright future ahead of him."
Carmona, who was ticketed to open the season as the No. 1 starter at Triple-A Buffalo until left-hander Cliff Lee went down with an injury, has tweaked his delivery and believes the changes will help him during the coming season.
The change helped improve Carmona's performance enough to convince Wedge and the Indians that the right-hander deserves to start in a season-opening rotation that will also include C.C. Sabathia, Jake Westbrook, Jeremy Sowers and Paul Byrd.
"He's a guy that has really been able to go out and work on what he needs to work on, and continue to improve, and that's what we've seen this spring," Wedge said.
Jim Molony is a writer for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.