Blake, 35, gives Detroit another point guard who can back up Reggie Jackson. The Pistons also have Brandon Jennings, but he's recovering from a major Achilles tendon injury, and Spencer Dinwiddie, whose NBA Summer League play has been uneven.
"Just insurance," Piston president Stan Van Gundy told the Detroit Free Press via text. "We're very hopeful that Brandon will play at a high level. And can develop Spencer, but not have pressure on him."
Blake, who is on the books for one season at $2.1 million, has played in 812 NBA games in 12 seasons. He averaged 4.3 points last season with the Portland Trail Blazers.
The Nets acquired him and the draft rights to forward Rondae Hollis-Jefferson on draft night from Portland for center Mason Plumlee and the draft rights to guard-forward Pat Connaughton, an Orioles prospect.
Miller, 22, played 10 games last season for the Sacramento Kings and the Pistons.