Lynch noted during a press conference Friday that the Niners remain third in available space under the salary cap despite the QB's new deal. The Cleveland Browns and New York Jets are the only two teams with more room, according to Spotrac.
He told reporters the front office will "continue to be aggressive" during the offseason.
Adam Schefter of ESPN provided full details of the Garoppolo extension:
Lynch also provided an early glimpse at the 49ers' pitch to potential signings.
"Heading into free agency, this is a big deal," he said. "It's 75 degrees and sunny and we got this guy [Garoppolo]—who wouldn't want to be here?"
The Niners posted a 6-10 record during the 2017 campaign, but that's not indicative of the team's potential heading toward next fall.
San Francisco finished the season on a five-game winning streak after Garoppolo, who was acquired in a trade with the New England Patriots in October, took over the starting job.
The 26-year-old Illinois native completed 67.4 percent of his throws for 1,560 yards with seven touchdowns and five interceptions across six appearances. His 96.2 passer rating would have ranked ninth in the NFL if he had enough playing time to qualify.
With the offense in the rising star's seemingly capable hands, Lynch and Co. will likely shift their focus to the defense in free agency and the draft.
The 49ers checked in 25th in points allowed, 24th in yards allowed and tied for 20th in takeaways during the 2017 season.
Dallas Cowboys defensive end DeMarcus Lawrence, Seattle Seahawks defensive tackle Sheldon Richardson and New England Patriots cornerback Malcolm Butler headline the potential defensive free agents.