"I'm done," he told The Telegraph. "That's how life goes I guess."
Miller, who started nine games as a sophomore, was forced out by chronic shoulder problems. He has had three surgeries on his left shoulder and one on his right.
After sitting out the 2004 season, he came back for spring practice and stayed healthy. However, on Monday, he had a relapse in both shoulders.
"It's not really a pain thing," he said. "It was more of a thing where I couldn't use my shoulders. It's kind of like a stinger. Your arms just go dead."
"He knows he won't be able to hold up, and we're very sorry about that," coach Mark Richt said of Miller, who listed third on the depth chart at guard. "I mean, (defensive tackle) Gerald Anderson is 310 pounds. When you have to try to stop that bull rush, you have to use those arms. It's just a lot of strain on those arms."
Miller talked with his parents and team doctors Monday night, and then met with offensive line coach Neil Callaway to inform him he had decided overnight to quit the game.
"It seemed like it was time to call it quits, to keep from hurting myself worse," he said. "It was already kind of in my head, but it was a tough decision. You're kind of throwing away a little bit of who you are."
Miller, who was a first-team all-state performer at Marist in 2001, played regularly as a true freshman and seemed destined to be a three-year starter before his injuries began to mount. He plans to work with the team as a volunteer coach until he graduates next year. He then will join his father's insurance business in Atlanta, he said.
Miller currently has a slight tear in either the rotator cuff or labrum in his right shoulder, but it shouldn't require surgery, he said.