Both were named broadcast analysts on Wednesday.
The 36-year-old Harrison, often called the NFL's dirtiest player, retired Wednesday after 15 seasons.
He was a three-time All-Pro and a two-time Super Bowl champion in six seasons with the Patriots after playing his first nine years with the San Diego Chargers.
Harrison finished his career with 1,205 tackles, 34 interceptions and 30 1/2 sacks, making him the only player ever with 30 sacks and 30 interceptions in a career.
Dungy retired from the Colts at the end of the 2008-09 after qualifying for the playoffs in each of the last 10 seasons, seven with Indianapolis and three with Tampa Bay.
"It's a remarkable feat that Tony's teams made the playoffs for 10 straight seasons, given that he was playing a first-place schedule most years and under a salary cap," NBC Sports Dick Ebersol said during a conference call.
"If I were running a team, what I know about (former Atlanta quarterback) Michael Vick and what I've seen from him, I would definitely give him an opportunity to play," Dungy, an ordained minister, said.
Vick was suspended after a dogfighting conviction and is under house arrest in Surry County, Virginia.