"Not surprised," he said of Brady joining the Tampa Bay Buccaneers, per Mike Reiss of ESPN.com. "A player like him, playing somewhere that long, you never can see it, but it shows you that in the National Football League it can be anyone going somewhere. It's a business, and that's how you have to look at it."
Unless New England adds someone through free agency or the NFL draft, the quarterback job will come down to Jarrett Stidham, Brian Hoyer and Cody Kessler.
That's not exactly a list of signal-callers who can challenge Brady in the greatest-of-all-time discussion, but Gilmore likes what he's seen of Stidham in practice ever since the Patriots selected him with a fourth-round pick in last year's draft.
"He came in and worked hard and got better and better as the year went on. He has a strong arm," Gilmore said. "He makes some tough throws. Definitely made it hard on me in practice each and every week, going against whoever I was covering, making some great throws. It allowed me to get better in practice to prepare for the games."
While Brady's departure is the primary storyline surrounding the Patriots heading into the 2020 campaign given his legendary status, they are still positioned to challenge in the AFC if Gilmore and the defense play like they did last year.
New England led the league in yards allowed and points allowed last season on the way to an 11th straight AFC East crown.
Gilmore, who made his third career Pro Bowl and was named Defensive Player of the Year, was a primary reason that unit was so tough on opposing offenses. He frequently lined up across the opponent's best receiver and finished the season with six interceptions, 20 passes defended and two defensive touchdowns.
The pressure will be on him and the rest of the defense to replicate that performance now that Brady is no longer there guiding the offense.