Marshawn Lynch just said he's "in talks" with the Seattle Seahawks about yet another NFL comeback ... this time telling ESPN's Scott Van Pelt to "expect the unexpected" from him in 2020.

"Just as far as right now," Lynch said Monday, "what I do know is, imma keep it solid. My agent has been in talks with Seattle, so like I said, we'll see what happens."

Lynch has retired and unretired multiple times in his NFL career ... but after his short stint with the 'Hawks at the end of last season, most thought the 34-year-old was officially done.

But, Lynch sure seems like a guy who wouldn't mind making a run at Year No. 13 in the NFL.

"If it works out and I get back up there, it is what it is," Lynch said. "And, if not, sh*t, I'm looking good. So I ain't really trippin' too much."

Marshawn -- who's had a Hall of Fame-caliber career -- famously quit the NFL after the 2015 season ... but came back to the Oakland Raiders in 2017 after sitting out all of '16.

After playing 21 games for Oakland in two seasons, it appeared Lynch was finally done with football ... but then he surprisingly returned to Seattle to help with their playoff run last year.

AND, HE LOOKED GOOD!!

So, could he come back for a full season this time with the 'Hawks???