Miller, who was placed on the DL with a strained left flexor muscle on June 10, made 25 flat-ground throws from 60 feet Wednesday morning. He said he was pain-free and plans to throw again on Thursday.
"I'll throw a little bit more tomorrow, then an off-day, then just kind of build up, make a progression," Miller said.
The Yankees haven't publicly discussed any timetable for Miller's return, but he figures to throw off a mound in the next seven or eight days. The goal is to not rush back, he said.
"I'm sure there's an ideal situation, then there's reality," Miller said. "Assuming I recover well and everything goes well, I still think that you just don't know."
A flexor muscle is one of a group of muscles below the elbow that allows the arm to bend and the hand to flex. At the time of Miller's injury, Yankees manager Joe Girardi emphasized the ligament around the muscle was healthy, but the muscle itself had a small strain.
Before the injury, Miller was one of the most effective closers in the Major Leagues, tallying 17 saves in as many chances. He allowed just three runs in 26 1/3 innings, striking out 43 batters and walking 10.
Dellin Betances has filled in at closer in Miller's absence, recording two saves in two chances.