It is believed Miller received better offers from the Denver Nuggets and Houston Rockets but turned them down for a chance to again play alongside LeBron James, Miller's former teammate with the Miami Heat.
James, who agreed to a two-year deal in free agency with the Cavs last week, was said to play a role in the recruitment of Miller. Both were members of the Heat's back-to-back championship teams in 2011-12 and '12-13. Miller, 34, spent last season with the Memphis Grizzlies. He played in all 82 regular-season games and averaged 7.1 points and shot 46 percent on 3-pointers.
The Cavs and Nuggets were said to be the frontrunners for Miller, selected fifth overall by the Orlando Magic in the 2000 draft.
"Unless something unforeseeable happens, he will be joining (the Cavs)," a league source told FOX Sports Ohio last Friday.