Star Jacksonville defensive end Arik Armstead is thrilled the Jaguars got two-way phenom Travis Hunter ... telling TMZ Sports he's super pumped to welcome his new teammate -- even if the Heisman winner doesn't spend much time on his side of the ball.

"I think this is rare air," Armstead -- who actually announced the big pick at the draft -- told us. "We have a player here who would have been a first-round pick as a receiver or a cornerback. And, you know, that's very unlikely that a prospect could be a first-round pick at two different positions."

So, where do you utilize a guy who is awesome on offense and defense? We asked Arik.

"[Jags head coach Liam Coen] came out and said that they want to start him off on offense and sprinkle him into defense. I think that's the plan they have for [Travis], and we're excited to have him. And, you know, it's going to be a bit of a transition for him like it is for all of us rookies in the NFL, but he's a dynamic player. And, I think he's going to add a different element to our team that's going to be very exciting."

Of course, the Jags were originally set to pick at 5 ... and Hunter would've been off the board by then. But, team brass clearly had their minds made that they wanted Trav ... and thanks to a big trade with the Browns, they were able to jump up three picks and get their guy.

Arik, who was hanging backstage with Lil Wayne and NFL commissioner Roger Goodell, got word he'd have to grace the stage a bit early 'cause of the pick swap -- and he knew immediately what that meant.

"Everyone knew once we traded up to two who we were getting and that was Travis Hunter."

Check out the interview with former first-round draft pick ... Arik and Babcock talk about how Hunter will impact the defense, especially when it comes to hauling in picks.