He's been skating lightly on his own over the past week, but was in full equipment and taking shots during Monday's workout. Miller has been out since sustaining a high ankle sprain against the New York Rangers on Feb. 21.
He didn't give a timetable for when he would be ready to play in a game.
"My plan is to get in as quick as possible, but I really can't tell you when that's going to be," Miller said. "It's all dependent on how quickly I get myself up to speed and how my ankle reacts. You don't want to do anything too quick."
The Sabres have gone into a tailspin since Miller was sidelined when Rangers forward Scott Gomez upended him behind the Buffalo net early in the third period. Buffalo has dropped below the Eastern Conference playoff cutoff line with just a 3-7-2 mark during his absence.
"We're trying to go day by day and evaluate it," he said. "We're going to see how it reacts over the whole day. I was excited about being out there today, but it was a little bit more tender than I thought. I just have to learn how to deal with that stuff."
The Sabres have plummeted to 10th place in the East, and are five points behind eighth-place Montreal in the race for the final postseason slot. They've wilted over the past seven games (1-5-1), putting them in danger of missing the playoffs for the second straight year after they reached the conference finals the previous two seasons.
"Sitting out the last month has been eating away at me and I want to be out there," Miller said. "But I want to be smart. A goalie who is not 100 percent right now is not what we need."
Backup Patrick Lalime has started all but one of the 12 games that Miller has missed. He was sharp early on, posting a .949 save percentage in his first five games, highlighted by back-to-back 5-1 wins over Montreal and Phoenix. But Lalime has just a 4.35 goals-against average and .865 save percentage in his last six starts.
Buffalo has 10 games left in the regular season, starting Wednesday when it hosts ninth-place Florida. The Panthers are four points in front of the Sabres.
"That's a real big game," Sabres coach Lindy Ruff said. "We're still right there. It isn't as big a task as you would think as long as you win the games you need to win. Obviously we haven't won recently, but we can start Wednesday."