Triplett reported Unger said he has "been dealing with the maintenance of a lower-body injury for a while and doctor recommended surgery that would take full offseason to recover." Triplett added Unger "didn't think he could do that and keep playing up to his standard."
Unger has been hiking footballs to quarterback Drew Brees since 2015. As a Saint, Unger has started 63 out of 64 possible regular-season games. He spent the first six seasons with the Seattle Seahawks, who selected him in the second round of the 2009 NFL draft.
The only positive the Saints can take from Unger's retirement is that his placement on the reserve/retired list relieves $6.95 million in salary-cap space, per Triplett, as $1.75 in dead money will still count against the team's cap.
Unger was entering the final season of his three-year, $22.2 million contract. He will turn 33 years old on April 14.
Unger's departure will leave a gaping hole along the Saints offensive line as Unger's 63 games with Brees make him the longest-tenured center of Brees' career. In December, Brees told Josh Katzenstein of the Times-Picayune of Unger, "He's the glue that holds a lot of what we do together."
Brees also credited Unger with extending his career and labeled him as the center young guys should strive to be like: "The center position really sets the tone. They set the tone for the whole O-line."
Last season marked Unger's first time being selected for the Pro Bowl as a Saint. He racked up 1,013 snaps in 2018, only marginally down from his 1,037 in 2017. Unger appeared in three Pro Bowls throughout his career and was named first-team All-Pro in 2012.
Moving forward, the Saints may turn to backup centers Cameron Tom or Will Clapp. Tom was signed by the Saints after going undrafted in 2017, while Clapp was selected in the seventh round of last year's draft.
When asked by a fan on Twitter in May last year, retired Saints offensive tackle Zach Strief named Tom as the offensive lineman soon to make a name for himself. That time now can't come soon enough from the team's perspective.
Rod Walker of the New Orleans Advocate pegged free-agent centers Stefen Wisniewski, John Sullivan, Ryan Groy and Tyler Shatley as potential targets. The Advocate's Nick Underhill tossed free agent Nick Easton, who has spent both his NFL seasons with the Minnesota Vikings, into the mix as well.
New Orleans does not own picks in the first round, third round or fourth round of the upcoming 2019 NFL draft.