Ian Rapoport of NFL Network first reported DeFilippo was expected to fill the vacant post on head coach Doug Marrone's staff.
DeFilippo spent the past season as the offensive coordinator for the Minnesota Vikings but was fired in early December after the team fell to 6-6-1 on the season.
The Vikings averaged 21.7 points per game during his time in charge but improved to 26 per game in the last three weeks under Kevin Stefanski.
It was the 40-year-old's second stint as an offensive coordinator in the NFL, while the other one was also brief. He served the role with the Cleveland Browns in 2015, leading the 3-13 team to the second-worst offense in the league.
However, DeFilippo has plenty of experience as a quarterbacks coach, working for three NFL teams in that role as well as several college programs, most notably San Jose State. He most notably served as a coach for the Philadelphia Eagles in 2016 and '17, helping develop Carson Wentz into an MVP candidate and Nick Foles into a Super Bowl MVP.
He also has a long history working with rookie quarterbacks, including Derek Carr and Mark Sanchez.
Whether the Jaguars stick with Blake Bortles or draft a replacement early, DeFilippo will try to get the most out of the position.
With Jacksonville finished last season fourth in total points allowed but 31st in points scored, it's clear the offense has a lot of work to do to hold up its end of the bargain. The latest addition will hopefully help provide some balance and get back to the playoffs.