Bucs legend Ronde Barber is STOKED ... telling TMZ Sports his squad just became serious Super Bowl contenders!

Of course, Ronde is one of the all-time Bucs greats -- spending 16 seasons in Tampa and winning a Super Bowl in the process.

But, the former defensive back admits his beloved squad hasn't exactly been relevant on a national level in years ... UNTIL NOW, BABY!!!

"You don't sign Tom Brady to a team that has this much talent ... without the expectation that you wanna win a Super Bowl," Barber says.

"They have talent on this football team. And, an emerging defense. I would say the expectation is to win this year."

Ronde also points out how bringing in Gronk and TB12 will ensure the Bucs get a chance to thrive on the national stage!

"When has Tony Romo ever been here? Has he done a game here in Tampa? Best analyst in football and I think he's been here one time. Those types of things will change."

"'Monday Night Football' will come here. 'Sunday Night Football' will come here. These types of things are gonna drive the energy for the Bucs franchise here in 2020."

By the way, Ronde's only 45 years old -- just 3 years older than Tom. So, has he considered dusting off the cleats and getting back on the field?