To make room on the roster, the Nuggets are expected to waive guard Jameer Nelson, per Wojnarowski.
"I'm sacrificing my way out of here," he said during an episode of his Road Trippin' podcast with Channing Frye (via ESPN's Dave McMenamin).
Wojnarowski had reported the Hawks were going to waive Jefferson, who was due to make $2.5 million this season.
The Cavs needed to get their roster down to 15 players by the end of the preseason. The late signing of Dwyane Wade left them with one player too many.
Jefferson has proved to be a valuable role player, especially over the past two seasons coming off Cleveland's bench. He shot 38.2 percent from three-point range during the Cavs' 2015-16 championship season.
In Cleveland's one victory over the Golden State Warriors in the 2017 NBA Finals, Jefferson was the main defender against Kevin Durant. He held the Warriors' superstar to 1-of-7 shooting in that game as the primary defender.
"[Durant's] one of the best talents that this league has seen," Jefferson told reporters about Game 4. "It's the same with guarding LeBron. I had to do that. All the high-level small forwards. Carmelo [Anthony]. These are guys that are very different players. They're all very unique talents, and so you have your hands full when you get that opportunity to guard them."
With 16 seasons of experience already under his belt, Jefferson has shown he can play multiple roles. His minutes have to be carefully managed because of his advanced age, but there's no reason to think he won't be able to give the Nuggets 15-20 solid minutes on both sides of the ball each night.
Jefferson's arrival in Denver should not be a surprise. He played for the Golden State Warriors for two seasons in 2011-12 and 2012-13 when Nuggets head coach Michael Malone was an assistant for Mark Jackson.
The Nuggets can use an established veteran like Jefferson, who has won an NBA championship and has seen everything in his career, to help their young talent continue to take steps forward as they look to make the playoffs after just missing out last season with a 40-42 record.
Denver's success depends on Nikola Jokic continuing his evolution into one of the NBA's best centers and Gary Harris taking another step after averaging 14.9 points per game last season while shooting 42 percent from three-point range.
Jefferson gives the Nuggets depth at small forward to ease some of the burden on veteran Wilson Chandler and defensive versatility.