Ben -- a huge Seahawks fan -- spoke with TMZ Sports just hours after the trade that sent the 9x Pro Bowl QB and a fourth-round pick to Denver in exchange for 3 players, 2 first-round picks, 2 second-round picks and a fifth-round.

"One of the worst trades in NFL history," Ben said Tuesday in Studio City, "and definitely the worst trade in Seahawks history."

Ben's also not too fond of swapping Wilson for QB Drew Lock ... saying there's no way the former Mizzou star is a starting QB.

FYI, Lock has started 21 games for Denver since 2019 -- throwing 25 TD's (he also ran for 5), and 20 interceptions. He's been sacked 33 times.

"C'mon bro. Like if he suits up, I'm gonna throw tomatoes at this guy," Ben said.

The 49-year-old basically says he wants anyone but Lock ... and even throughout a few potential Wilson replacements.

"I'm hoping that we may pick up Deshaun Watson, somehow someway we manifest that. I'd rather have Geno Smith. There's no way that Drew Lock is gonna be QB1 for us," Ben says.

"How do you replace a Hall of Famer?!"

Ben believes the 33-year-old QB could bring the Lombardi Trophy back to Denver -- something that hasn't happened since 2016 with Peyton Manning.

"I think so, bro," Ben tells us, "It's not far-fetched."