Ravens tight end Darren Waller has been suspended without pay by the NFL for at least one year after violating the league’s substance abuse policy for a second time in two years.

Waller, 24, is eligible to participate in all preseason practices and games, but will not be allowed around the team once the regular-season begins.

The 6-foot-6, 255-pound Georgia Tech product was suspended for the first four games of last season. He returned to catch 10 passes for 85 yards and two touchdowns.

The 2015 sixth-round pick has immense potential – he’s one of the team’s most athletically freakish players given his size and speed – but a second suspension could derail his career.

It’s unknown what Waller specifically did to violate the substance abuse policy. After serving his last suspension, he was frank about marijuana use and said he was beyond it.

“There were other personal issues, and [marijuana] was the one thing I always turned to,” Waller said in October. “It was just about finding more positive outlets for me to do, like talking to people about it and things like that. I’m definitely at a better place with that now.

“It’s knowing that it’s bigger than me around here. When I’m here, it’s not a problem. I work hard and am involved in everything and positive. But when I leave here, am I still taking that mindset with me wherever I go?”

The Ravens concluded minicamp two weeks ago and veterans have been out of the building since that time.