"If I was [Gates] I'd probably be done, but if he feels like he wants to play, play," the 42-year-old told TMZ Sports.
Gates' agent Tom Condon told Alex Marvez of SiriusXM NFL he was "actively negotiating" a deal in July, but he still hasn't come to an agreement with the Chargers.
The 15-year veteran has spent his entire NFL career with the Chargers and doesn't appear to be looking elsewhere for a job, although the season-ending injury to Hunter Henry apparently hasn't forced the team's hand in negotiations.
Gonzalez, who retired after 17 years in the league with 14 Pro Bowl selections, noted he "probably would" retire if he were in Gates' shoes, although perhaps he is just trying to hold onto his record for most receptions and receiving yards for a tight end. Gates already broke the future Gonzalez's record for most touchdowns at the position.
Meanwhile, Gonzalez also has thoughts on his former team, the Kansas City Chiefs. He has especially been impressed in what he has seen from new quarterback Patrick Mahomes.
"He's going to be outstanding," Gonzalez said of the second-year player.
Mahomes was the 10th overall pick in the 2017 draft but only played one game last year while sitting behind Alex Smith. However, he clearly showed enough for the team to trade Smith to the Washington Redskins, opening the door for a big season.
"He's probably going to throw a lot of picks, but he's going to throw a lot of touchdowns, too," Gonzalez predicted for the upcoming season.
Considering Gonzalez's vast experience in the NFL, his words should be a major compliment for the unproven passer.