Puig is a right fielder who's been trade bait for the Dodgers in previous years who's listed to make about $11 million in the final year of his contract.
The Dodgers' payroll will still exceed $180 million after the deal, according to Passan, so landing Harper - who is expected to demand a historic deal that could exceed $400 million - is far from guaranteed.
Dealing two outfielders increases the speculation that free agent Bryce Harper could end up choosing Los Angeles. He quickly became a fan favorite while helping Los Angeles to a pair of NL pennants, despite his overall rocky relationship with the team.
Earlier Friday, the Dodgers' Andrew Friedman sent starting pitcher Alex Wood and his two most decorated outfielders, Yasiel Puig and Matt Kemp, to the Reds. For the Reds, it's another move toward becoming competitive after four straight 90-loss seasons.
Miller, 33, posted an ERA of 4.24 last season but had not posted an ERA above 2.04 from 2014-17, including a stellar 10-1 season with a 1.45 ERA between the New York Yankees and Cleveland Indians in 2016.
Reds president of baseball operations Dick Williams said following the deal that the Reds aren't done making moves. "We did trade some good prospects here, but we acquired four major-league players that address needs for us and I think we're better in the short term". He could help stabilize a Reds rotation that was 23rd in the league in team ERA.
Kemp, 34, batted.290 with 25 doubles, 21 homers and 85 RBIs last season, when he was an All-Star for the third time.