Raiders' Darren Waller on Addiction Battle, 'I'm Living with a Purpose'

Oakland Raiders tight end Darren Waller says he's GLAD the world knows about his battle with substance abuse ... because he's inspiring others and it "feels like I'm living with a purpose."

Waller's story is incredible ... the 26-year-old is insanely talented but almost watched his career go down the toilet after multiple violations of the NFL's substance abuse policy over the years.

The Raiders gave him a shot in late 2018 and now he's become a key part of the Oakland offense ... catching 7 passes for 70 yards in the Week 1 win over the Broncos.

Waller's addiction issues were featured on the HBO series "Hard Knocks" -- and Darren tells TMZ Sports the reaction has been amazing.

"A lot of people are reaching out relating to my story and that’s the kind of stuff that makes me feel like I’m living with a purpose," Waller says.

"When I go out there, I kind of try and do it for them."

Waller says he still makes it a point to attend AA meetings and other support groups regularly -- even when the team is on the road.

And, get this ... Waller says he never expected a second chance in the NFL, but now that he's got it -- he's determined to make the most of it. He's making sure to use all resources available to him to stay sober, understanding it's a constant battle.

As for the football side of things, Waller says he ain't surprised by the Raiders' performance in Week 1 -- even without Antonio Brown -- saying the guys busted their asses all offseason and don't want to let the fans down!