Martellus made the remarks when he joined his former Patriots teammates, Devin and Jason McCourty, on their "Double Coverage" podcast ... claiming no NFL team can win with Jimmy G at the helm because he believes the signal-caller is soft.

Bennett went on to explain he developed that opinion following the way Garoppolo filled in for Tom Brady during the GOAT's four-game suspension back in the 2016 season.

You'll recall, Garoppolo helped the Pats win the first two games of the season ... but he injured his non-throwing shoulder in Week 2, and sat out the ensuing two games due to the ailment -- something Bennett clearly thinks was a no-no.

"We lost two games," Bennett said. "One of them is because Jimmy Garappolo was being a bitch. He quit before us on the last -- decided not to play right before the game."

"So, we went out there, Jacoby [Brissett] came out and played with a f***ked-up thumb, [and] played his heart out. But, Jimmy was just being a bitch about it all."

Bennett added, "And he's still being -- like, that's why, you can't win with a bitch for a quarterback."

Julian Edelman, who played alongside Bennett on the Pats, was asked about Martellus' feelings toward Jimmy on a recent episode of the "I Am Athlete" podcast ... and the 3x Super Bowl champ said he felt similarly to Bennett.

"A lot of guys got mad about it," Edelman said. "I'm not going to lie, I got mad about it. I sacrifice my body all day long. I was taking shots for this, numbing up that."

"Ribs, broken ribs, shoulders. You know, Grade 3, hanging on by limbs, just to play," Edelman said. "And, you know, I can understand why Marty thinks like that."